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Sample records for abbot prism chagas

  1. Prism

    NASA Astrophysics Data System (ADS)

    Kuno, Yoshitaka

    2000-11-01

    The PRISM project in Japan to consider a high-intensity low-energy muon source is discussed. PRISM would include solenoid pion capture and phase rotation to create a muon beam of 1012μ±/sec with high purity and small energy spread, if it is combined with the planned 50-GeV proton synchrotron in the KEK/JAERI Joint Project. The PRISM could be extended to a front end of a neutrino factory in the future.

  2. James Abbot McNeill Whistler: "At the Piano."

    ERIC Educational Resources Information Center

    Hallenberg, Heather

    1987-01-01

    "At the Piano," an oil-on-canvas painting completed in 1859 by James Abbot McNeill Whistler, is used as the basis of a lesson designed to help junior high school students analyze the painting's mood, subject matter, and composition. (JDH)

  3. Chagas Disease

    MedlinePlus

    Chagas disease is caused by a parasite. It is common in Latin America but not in the United States. ... nose, the bite wound or a cut. The disease can also spread through contaminated food, a blood ...

  4. Bathymetric and oceanic controls on Abbot Ice Shelf thickness and stability

    NASA Astrophysics Data System (ADS)

    Cochran, J. R.; Jacobs, S. S.; Tinto, K. J.; Bell, R. E.

    2014-05-01

    Ice shelves play key roles in stabilizing Antarctica's ice sheets, maintaining its high albedo and returning freshwater to the Southern Ocean. Improved data sets of ice shelf draft and underlying bathymetry are important for assessing ocean-ice interactions and modeling ice response to climate change. The long, narrow Abbot Ice Shelf south of Thurston Island produces a large volume of meltwater, but is close to being in overall mass balance. Here we invert NASA Operation IceBridge (OIB) airborne gravity data over the Abbot region to obtain sub-ice bathymetry, and combine OIB elevation and ice thickness measurements to estimate ice draft. A series of asymmetric fault-bounded basins formed during rifting of Zealandia from Antarctica underlie the Abbot Ice Shelf west of 94° W and the Cosgrove Ice Shelf to the south. Sub-ice water column depths along OIB flight lines are sufficiently deep to allow warm deep and thermocline waters observed near the western Abbot ice front to circulate through much of the ice shelf cavity. An average ice shelf draft of ~200 m, 15% less than the Bedmap2 compilation, coincides with the summer transition between the ocean surface mixed layer and upper thermocline. Thick ice streams feeding the Abbot cross relatively stable grounding lines and are rapidly thinned by the warmest inflow. While the ice shelf is presently in equilibrium, the overall correspondence between draft distribution and thermocline depth indicates sensitivity to changes in characteristics of the ocean surface and deep waters.

  5. Composite Spectrometer Prisms

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Page, N. A.; Rodgers, J. M.

    1985-01-01

    Efficient linear dispersive element for spectrometer instruments achieved using several different glasses in multiple-element prism. Good results obtained in both two-and three-element prisms using variety of different glass materials.

  6. Mass balance reassessment of glaciers draining into the Abbot and Getz Ice Shelves of West Antarctica

    NASA Astrophysics Data System (ADS)

    Chuter, S. J.; Martín-Español, A.; Wouters, B.; Bamber, J. L.

    2017-07-01

    We present a reassessment of input-output method ice mass budget estimates for the Abbot and Getz regions of West Antarctica using CryoSat-2-derived ice thickness estimates. The mass budget is 8 ± 6 Gt yr-1 and 5 ± 17 Gt yr-1 for the Abbot and Getz sectors, respectively, for the period 2006-2008. Over the Abbot region, our results resolve a previous discrepancy with elevation rates from altimetry, due to a previous 30% overestimation of ice thickness. For the Getz sector, our results are at the more positive bound of estimates from other techniques. Grounding line velocity increases up to 20% between 2007 and 2014 alongside mean elevation rates of -0.67 ± 0.13 m yr-1 between 2010 and 2013 indicate the onset of a dynamic thinning signal. Mean snowfall trends of -0.33 m yr-1 water equivalent since 2006 indicate recent mass trends are driven by both ice dynamics and surface processes.

  7. Chagas' disease.

    PubMed Central

    Tanowitz, H B; Kirchhoff, L V; Simon, D; Morris, S A; Weiss, L M; Wittner, M

    1992-01-01

    Chagas' disease, caused by Trypanosoma cruzi, is an important cause of morbidity in many countries in Latin America. The important modes of transmission are by the bite of the reduviid bug and blood transfusion. The organism exists in three morphological forms: trypomastigotes, amastigotes, and epimastigotes. The mechanism of transformation and differentiation is currently being explored, and signal transduction pathways of the parasites may be involved in this process. Parasite adherence to and invasion of host cells is a complex process involving complement, phospholipase, penetrin, neuraminidase, and hemolysin. Two clinical forms of the disease are recognized, acute and chronic. During the acute stage pathological damage is related to the presence of the parasite, whereas in the chronic stage few parasites are found. In recent years the roles of tumor necrosis factor, gamma interferon, and the interleukins in the pathogenesis of this infection have been reported. The common manifestations of chronic cardiomyopathy are arrhythmias and thromboembolic events. Autoimmune, neurogenic, and microvascular factors may be important in the pathogenesis of the cardiomyopathy. The gastrointestinal tract is another important target, and "mega syndromes" are common manifestations. The diagnosis and treatment of this infection are active areas of investigation. New serological and molecular biological techniques have improved the diagnosis of chronic infection. Exacerbations of T. cruzi infection have been reported for patients receiving immuno-suppressive therapy and for those with AIDS. Images PMID:1423218

  8. Optical switch using Risley prisms

    DOEpatents

    Sweatt, William C.; Christenson, Todd R.

    2003-04-15

    An optical switch using Risley prisms and rotary microactuators to independently rotate the wedge prisms of each Risley prism pair is disclosed. The optical switch comprises an array of input Risley prism pairs that selectively redirect light beams from a plurality of input ports to an array of output Risley prism pairs that similarly direct the light beams to a plurality of output ports. Each wedge prism of each Risley prism pair can be independently rotated by a variable-reluctance stepping rotary microactuator that is fabricated by a multi-layer LIGA process. Each wedge prism can be formed integral to the annular rotor of the rotary microactuator by a DXRL process.

  9. Optical Switch Using Risley Prisms

    DOEpatents

    Sweatt, William C.; Christenson, Todd R.

    2005-02-22

    An optical switch using Risley prisms and rotary microactuators to independently rotate the wedge prisms of each Risley prism pair is disclosed. The optical switch comprises an array of input Risley prism pairs that selectively redirect light beams from a plurality of input ports to an array of output Risley prism pairs that similarly direct the light beams to a plurality of output ports. Each wedge prism of each Risley prism pair can be independently rotated by a variable-reluctance stepping rotary microactuator that is fabricated by a multi-layer LIGA process. Each wedge prism can be formed integral to the annular rotor of the rotary microactuator by a DXRL process.

  10. Project PRISM: PRISM's Annotated Resource List.

    ERIC Educational Resources Information Center

    Cunnion, Maryellen; And Others

    The final of three volumes on Project PRISM, a program to help middle school teachers meet the needs of gifted and talented children in their classes without removing them from the mainstream, lists resources on the education of gifted and talented children. Materials are organized according to four basic types: books, periodicals, curriculum aids…

  11. Prism users guide.

    SciTech Connect

    Weirs, V. Gregory

    2012-03-01

    Prism is a ParaView plugin that simultaneously displays simulation data and material model data. This document describes its capabilities and how to use them. A demonstration of Prism is given in the first section. The second section contains more detailed notes on less obvious behavior. The third and fourth sections are specifically for Alegra and CTH users. They tell how to generate the simulation data and SESAME files and how to handle aspects of Prism use particular to each of these codes.

  12. Prism adaptation by mental practice.

    PubMed

    Michel, Carine; Gaveau, Jérémie; Pozzo, Thierry; Papaxanthis, Charalambos

    2013-09-01

    The prediction of our actions and their interaction with the external environment is critical for sensorimotor adaptation. For instance, during prism exposure, which deviates laterally our visual field, we progressively correct movement errors by combining sensory feedback with forward model sensory predictions. However, very often we project our actions to the external environment without physically interacting with it (e.g., mental actions). An intriguing question is whether adaptation will occur if we imagine, instead of executing, an arm movement while wearing prisms. Here, we investigated prism adaptation during mental actions. In the first experiment, participants (n = 54) performed arm pointing movements before and after exposure to the optical device. They were equally divided into six groups according to prism exposure: Prisms-Active, Prisms-Imagery, Prisms-Stationary, Prisms-Stationary-Attention, No Conflict-Prisms-Imagery, No Prisms-Imagery. Adaptation, measured by the difference in pointing errors between pre-test and post-test, occurred only in Prisms-Active and Prisms-Imagery conditions. The second experiment confirmed the results of the first experiment and further showed that sensorimotor adaptation was mainly due to proprioceptive realignment in both Prisms-Active (n = 10) and Prisms-Imagery (n = 10) groups. In both experiments adaptation was greater following actual than imagined pointing movements. The present results are the first demonstration of prism adaptation by mental practice under prism exposure and they are discussed in terms of internal forward models and sensorimotor plasticity.

  13. PRISM Spectrograph Optical Design

    NASA Technical Reports Server (NTRS)

    Chipman, Russell A.

    1995-01-01

    The objective of this contract is to explore optical design concepts for the PRISM spectrograph and produce a preliminary optical design. An exciting optical configuration has been developed which will allow both wavelength bands to be imaged onto the same detector array. At present the optical design is only partially complete because PRISM will require a fairly elaborate optical system to meet its specification for throughput (area*solid angle). The most complex part of the design, the spectrograph camera, is complete, providing proof of principle that a feasible design is attainable. This camera requires 3 aspheric mirrors to fit inside the 20x60 cm cross-section package. A complete design with reduced throughput (1/9th) has been prepared. The design documents the optical configuration concept. A suitable dispersing prism material, CdTe, has been identified for the prism spectrograph, after a comparison of many materials.

  14. Chagas disease in prehistory.

    PubMed

    Ferreira, Luiz F; Jansen, Ana M; Araújo, Adauto

    2011-09-01

    The classical hypothesis proposes that Chagas disease has been originated in the Andean region among prehistoric people when they started domesticating animals, changing to sedentary habits, and adopting agriculture. These changes in their way of life happened nearly 6,000 years ago. However, paleoparasitological data based on molecular tools showed that Trypanosoma cruzi infection and Chagas disease were commonly found both in South and North American prehistoric populations long before that time, suggesting that Chagas disease may be as old as the human presence in the American continent. The study of the origin and dispersion of Trypanosoma cruzi infection among prehistoric human populations may help in the comprehension of the clinical and epidemiological questions on Chagas disease that still remain unanswered.

  15. Treatment of Chagas Cardiomyopathy

    PubMed Central

    Botoni, Fernando A.; Ribeiro, Antonio Luiz P.; Marinho, Carolina Coimbra; Lima, Marcia Maria Oliveira; Nunes, Maria do Carmo Pereira; Rocha, Manoel Otávio C.

    2013-01-01

    Chagas' disease (ChD), caused by the protozoa Trypanosoma cruzi (T. cruzi), was discovered and described by the Brazilian physician Carlos Chagas in 1909. After a century of original description, trypanosomiasis still brings much misery to humanity and is classified as a neglected tropical disease prevalent in underdeveloped countries, particularly in South America. It is an increasing worldwide problem due to the number of cases in endemic areas and the migration of infected subjects to more developed regions, mainly North America and Europe. Despite its importance, chronic chagas cardiomyopathy (CCC) pathophysiology is yet poorly understood, and independently of its social, clinical, and epidemiological importance, the therapeutic approach of CCC is still transposed from the knowledge acquired from other cardiomyopathies. Therefore, the objective of this review is to describe the treatment of Chagas cardiomyopathy with emphasis on its peculiarities. PMID:24350293

  16. PRISM project optical instrument

    NASA Technical Reports Server (NTRS)

    Taylor, Charles R.

    1994-01-01

    The scientific goal of the Passively-cooled Reconnaissance of the InterStellar Medium (PRISM) project is to map the emission of molecular hydrogen at 17.035 micrometers and 28.221 micrometers. Since the atmosphere is opaque at these infrared wavelengths, an orbiting telescope is being studied. The availability of infrared focal plane arrays enables infrared imaging spectroscopy at the molecular hydrogen wavelengths. The array proposed for PRISM is 128 pixels square, with a pixel size of 75 micrometers. In order to map the sky in a period of six months, and to resolve the nearer molecular clouds, each pixel must cover 0.5 arcminutes. This sets the focal length at 51.6 cm. In order for the pixel size to be half the diameter of the central diffraction peak at 28 micrometers would require a telescope aperture of 24 cm; an aperture of 60 cm has been selected for the PRISM study for greater light gathering power.

  17. Carlos Chagas: biographical sketch.

    PubMed

    Moncayo, Alvaro

    2010-01-01

    Carlos Chagas was born on 9 July 1878 in the farm "Bon Retiro" located close to the City of Oliveira in the interior of the State of Minas Gerais, Brazil. He started his medical studies in 1897 at the School of Medicine of Rio de Janeiro. In the late XIX century, the works by Louis Pasteur and Robert Koch induced a change in the medical paradigm with emphasis in experimental demonstrations of the causal link between microbes and disease. During the same years in Germany appeared the pathological concept of disease, linking organic lesions with symptoms. All these innovations were adopted by the reforms of the medical schools in Brazil and influenced the scientific formation of Chagas. Chagas completed his medical studies between 1897 and 1903 and his examinations during these years were always ranked with high grades. Oswaldo Cruz accepted Chagas as a doctoral candidate and directed his thesis on "Hematological studies of Malaria" which was received with honors by the examiners. In 1903 the director appointed Chagas as research assistant at the Institute. In those years, the Institute of Manguinhos, under the direction of Oswaldo Cruz, initiated a process of institutional growth and gathered a distinguished group of Brazilian and foreign scientists. In 1907, he was requested to investigate and control a malaria outbreak in Lassance, Minas Gerais. In this moment Chagas could not have imagined that this field research was the beginning of one of the most notable medical discoveries. Chagas was, at the age of 28, a Research Assistant at the Institute of Manguinhos and was studying a new flagellate parasite isolated from triatomine insects captured in the State of Minas Gerais. Chagas made his discoveries in this order: first the causal agent, then the vector and finally the human cases. These notable discoveries were carried out by Chagas in twenty months. At the age of 33 Chagas had completed his discoveries and published the scientific articles that gave him world

  18. Less-expensive Rochon prisms

    NASA Technical Reports Server (NTRS)

    Ammann, E. O.; Massey, G. A.

    1970-01-01

    Inexpensive Rochon prisms can be produced by substituting easily polished glass for one-half of the calcite. Reciprocal polarizing properties of a conventional Rochon prism are retained, and angular separation between ordinary and extraordinary rays is the same as in all-calcite prism.

  19. Fresnel prism use among orthoptists.

    PubMed

    Haller, Terra; Furr, Bruce A

    2014-01-01

    To better understand current uses of Fresnel prisms. A seventeen-question survey was completed by members of the American Association of Certified Orthoptists (AACO). Surveys were emailed to 211 orthoptists with a 36% response rate (n = 76). Prisms are used preoperatively to determine the surgical angle for 72% of respondents, 94% use prisms for postoperative misalignment. Prisms are used for incomitant deviations by up to 96% of respondents. The greatest patient objection to Fresnel use is reduced vision and distortion, not diplopia out of primary position. Of orthoptists surveyed, 99% use Fresnel prisms for near-distance disparity, 36% splitting prisms for upper and lower segments, and 40% encourage separate spectacles for near and distance. When deciding to grind prism, 66% wait more than one month. Ninety-nine percent of orthoptists use Fresnel prisms with adults, 67% use them with children. When correcting vertical and horizontal deviations, 70% of orthoptists rotate a prism over one lens. Fresnel prisms have a wide use among North American certified orthoptists, including use with pediatric patients. Incomitance is not a contraindication to Fresnel use. Orthoptists prefer rotating one prism to bilateral Fresnel prisms. © 2014 Board of regents of the University of Wisconsin System, American Orthoptic Journal, Volume 64, 2014, ISSN 0065-955X, E-ISSN 1553-4448.

  20. Reflection by Porro Prisms

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2010-04-01

    Students all know that reflection from a plane mirror produces an image that is reversed right to left and so cannot be read by anyone but Leonardo da Vinci, who kept his notes in mirror writing. A useful counter-example is the Porro prism, which produces an image that is not reversed.

  1. Dove prism heterodyne refractometer

    NASA Astrophysics Data System (ADS)

    Hsu, Cheng-Chih; Lee, Chia-Yun; Chu, Kuan-Ho; Wu, Tsai-Chen

    2015-10-01

    In this study, we proposed an alternative method, integrating a Dove prism and precision circular heterodyne interferometry, for measuring the refractive index and concentration of sodium chloride and hydrogen peroxide solutions with low phase error. Due to the optical properties of the Dove prism, the test light undergoes total internal reflection (TIR) at the interface between the test sample and the prism. The light beam travels in and out of the Dove prism while maintaining the same direction. Therefore, only slight alignment is required, leading to only small errors in the phase and refractive index. In this study, the phase error, refractive index error, and resolution of the concentration are approximated to be 0.003°, 2×10-5, and 1×10-3 M, respectively. The proposed method has the advantages of a simple optical configuration, ease of operation, little alignment required, and high stability, and it allows for high-precision measurement of the refractive index and concentration of the liquid sample.

  2. Acoustic dispersive prism

    NASA Astrophysics Data System (ADS)

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  3. Acoustic dispersive prism.

    PubMed

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R

    2016-01-07

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  4. Generalization of Prism Adaptation

    ERIC Educational Resources Information Center

    Redding, Gordon M.; Wallace, Benjamin

    2006-01-01

    Prism exposure produces 2 kinds of adaptive response. Recalibration is ordinary strategic remapping of spatially coded movement commands to rapidly reduce performance error. Realignment is the extraordinary process of transforming spatial maps to bring the origins of coordinate systems into correspondence. Realignment occurs when spatial…

  5. Prism Adaptation in Schizophrenia

    ERIC Educational Resources Information Center

    Bigelow, Nirav O.; Turner, Beth M.; Andreasen, Nancy C.; Paulsen, Jane S.; O'Leary, Daniel S.; Ho, Beng-Choon

    2006-01-01

    The prism adaptation test examines procedural learning (PL) in which performance facilitation occurs with practice on tasks without the need for conscious awareness. Dynamic interactions between frontostriatal cortices, basal ganglia, and the cerebellum have been shown to play key roles in PL. Disruptions within these neural networks have also…

  6. Prism Adaptation in Schizophrenia

    ERIC Educational Resources Information Center

    Bigelow, Nirav O.; Turner, Beth M.; Andreasen, Nancy C.; Paulsen, Jane S.; O'Leary, Daniel S.; Ho, Beng-Choon

    2006-01-01

    The prism adaptation test examines procedural learning (PL) in which performance facilitation occurs with practice on tasks without the need for conscious awareness. Dynamic interactions between frontostriatal cortices, basal ganglia, and the cerebellum have been shown to play key roles in PL. Disruptions within these neural networks have also…

  7. Project PRISM: Project Manual.

    ERIC Educational Resources Information Center

    Cunnion, Maryellen; And Others

    The first of three volumes of Project PRISM, a program designed to help classroom teachers (grades 6 through 8) provide for the needs of their gifted and talented students without removing those students from the mainstream of education, outlines the project's background and achievements. Sections review the following project aspects (sample…

  8. Project PRISM: Parent Information.

    ERIC Educational Resources Information Center

    Cunnion, Maryellen; And Others

    The second of three documents on Project PRISM, a program designed to help middle school classroom teachers provide for the needs of gifted and talented students without removing them from the mainstream, notes guidelines for parents. The following topics are addressed (sample subtopics in parentheses): characteristics of the gifted (common myths…

  9. Generalization of Prism Adaptation

    ERIC Educational Resources Information Center

    Redding, Gordon M.; Wallace, Benjamin

    2006-01-01

    Prism exposure produces 2 kinds of adaptive response. Recalibration is ordinary strategic remapping of spatially coded movement commands to rapidly reduce performance error. Realignment is the extraordinary process of transforming spatial maps to bring the origins of coordinate systems into correspondence. Realignment occurs when spatial…

  10. Acoustic dispersive prism

    PubMed Central

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium. PMID:26739504

  11. Immunology of Chagas' disease*

    PubMed Central

    1974-01-01

    After reviewing present knowledge of the morphology, multiplication, and transmission of Trypanosoma cruzi, this Memorandum discusses the animal models that may be of value in understanding the immune mechanisms operating in Chagas' disease. The role of both circulating antibody and cell-mediated immunity in protection against the parasite is discussed, together with the possibility that immunopathological mechanisms may be responsible for some of the lesions found in patients with Chagas' disease. The immunodiagnostic methods at present available are also reviewed, and the possibility of producing a vaccine for human use is considered in the light of recent findings in experimental animals. A series of recommendations for further research is included. PMID:4218137

  12. Refraction, including prisms.

    PubMed

    Hiatt, R L

    1991-02-01

    The literature in the past year on refraction is replete with several isolated but very important topics that have been of interest to strabismologists and refractionists for many decades. The refractive changes in scleral buckling procedures include an increase in axial length as well as an increase in myopia, as would be expected. Tinted lenses in dyslexia show little positive effect in the nonasthmatic patients in one study. The use of spectacles or bifocals as a way to control increase in myopia is refuted in another report. It has been shown that in accommodative esotropia not all patients will be able to escape the use of bifocals in the teenage years, even though surgery might be performed. The hope that disposable contact lenses would cut down on the instance of giant papillary conjunctivitis and keratitis has been given some credence, and the conventional theory that sclerosis alone is the cause of presbyopia is attacked. Also, gas permeable bifocal contact lenses are reviewed and the difficulties of correcting presbyopia by this method outlined. The practice of giving an aphakic less bifocal addition instead of a nonaphakic, based on the presumption of increased effective power, is challenged. In the review of prisms, the majority of articles concern prism adaption. The most significant report is that of the Prism Adaptation Study Research Group (Arch Ophthalmol 1990, 108:1248-1256), showing that acquired esotropia in particular has an increased incidence of stable and full corrections surgically in the prism adaptation group versus the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. The anatomy of a hydrothermal (explosion ) breccia, Abbot Village, central Maine

    SciTech Connect

    Roy, D.C. . Dept. of Geology and Geophysics)

    1993-03-01

    An apparently intrusive hydrothermal breccia is exposed in a large outcrop along Kingsbury Stream downstream from the Route 6 bridge in Abbot Village. The breccia intrudes the Siluro-Devonian Madrid Formation which is comprised of thick-bedded metasandstone interbedded with less fine-grained schist and phyllite at regional biotite grade. In the vicinity of the breccia, the bedding attitude in the Madrid is N60E 70SE and the section faces SE. The breccia is a concordant body with respect to bedding and the exposure shows what appears to the SW terminus of the intrusion which extends an unknown distance NE. The main phase of the breccia consists of randomly oriented and angular clasts'' of Madrid metasandstone and schist that are cemented by a quartz-dominated matrix. The random orientation of the clasts is present this phase were it is in contact with the country rock. The matrix comprises about 15% of the volume of the breccia and, in addition to quartz, contains biotite, galena, chalcopyrite ( ), pyrite, and an iron-carbonate. In some interstitial matrix, apparently late iron-carbonate fills post-quartz vugs that contain quartz-crystal terminations. The wall phase contains a higher proportion of biotite schist clasts that in places are bent around each other and metasandstone clasts. Quartz veins extending into the country rock near the breccia follow prominent regional joint directions and suggest hydrofracturing of the Madrid was the principal mechanism for breccia formation. The breccia is interpreted to be of explosive origin with the main phase of the body representing clasts that fell down within the vent'' following upward transport. The wall phase is taken to have formed due to adhesion to the wall of breccia clasts during the eruptive stage.

  14. Synthesis of tetraethyl pyrophosphate (TEPP): from physician Abbot and pharmacist Riegel to chemist Nylen.

    PubMed

    Petroianu, G A

    2015-06-01

    Tetraethyl pyrophosphate (TEPP) made history not only as the first man-made organophosphate cholinesterase inhibitor but also as a most successful commercial product traded under a good number of names. The substance was first synthesized by a Russian chemist, Wladimir Petrovich Moshnin, while studying in Paris as an eleve (student) of Wurtz. The synthesis was soon thereafter repeated and reported to the Academy of Sciences by Philippe de Clermont, another student of Wurtz, who acknowledged the earlier work of Moshnin. Holmstedt in his chapter dealing with the beginnings of organophosphate chemistry in Koelle's Textbook Cholinesterases and Anticholinesterase Agents concluded his remarks by noting that after the initial synthesis by Moshnin and de Clermont, over the years, a good half-a-dozen of other pharmacists and chemists also managed the feat (of synthesizing TEPP). This led to my attempts at identifying those involved in the synthesis of TEPP. The compiled list turned out to be quite long: Abbot (1879), Riegel (1896), Cavalier (1906), Rosenheim A, Stadler & Jacobsohn (1906), Rosenheim & Pritze (1908), Balareff (1914), Nylen (1930), Arbusow & Arbusow (1931), Schrader (1938), Woodstock (1946) and Toy (1948). This report while summarizing the synthetic approach used in obtaining TEPP by the respective scientists mainly attempts to shed light on the life of the less known pharmacists and chemists involved in the synthesis of TEPP. The focus is on the pre-industrial synthesis period ending with Nylen largely because details on the Arbusow family, as well as on Schrader and Toy are fairly well known or have recently been described.

  15. Paleomagnetic constraints on rotation within Mount Abbot quadrangle, central Sierra Nevada, California

    USGS Publications Warehouse

    Ross, Stephanie L.

    1988-01-01

    The regional photolineament pattern in Mount Abbot quadrangle in the central Sierra Nevada is sigmoidal in plan view. The fractures in the southwest section of the quadrangle, near Florence Lake, strike N10°–20°E, while those in the central section, along Bear Creek, strike N50°–70°E and those in the northeast strike N25°–40°E. A paleomagnetic investigation was undertaken to determine if this sigmoidal pattern was formed by kinking of originally straight photolineaments after the rock mass cooled below the blocking temperature. If the inner limb of the kink rotated 40°–60° clockwise with respect to the outer limbs, then there should be a similar difference in the paleomagnetic declinations between the Florence Lake and Bear Creek areas. The paleomagnetic results indicate a clockwise difference in declination of 13.4°±7° of the Bear Creek area with respect to Florence Lake. Thus the sigmoidal pattern could not have formed entirely by rotation after cooling below the blocking temperature. It is also possible that the observed declination discrepancy is due to tilting, apparent polar wander, or paleomagnetic dispersion instead of rotation. Sigmoidal patterns, formed by kink folding, occur on the outcrop scale with inner limb rotations of 15°–30°; three of these kinks were sampled to test the paleomagnetic method in an area of demonstrable rotation. The data from these sites indicate that although no difference in declination is evident, a reheating event may have occurred which could have removed any rotation from the paleomagnetic record. Reheating, possibly due to the circulation of hydrothermal fluids, may have been causally related to the outcrop scale kinking, since reheating is not observed away from the outcrop scale kinks. The data further indicate that there may have been continuous deformation of the rock mass during the formation of the kinks.

  16. Immunity in Chagas’ Disease.

    DTIC Science & Technology

    This is the final report on the immunity in Chagas ’ disease contract and it summarizes the results of a diversity of studies directed toward...antibody test for Chagas ’ disease. Also mentioned are the facts that the cell membranes of live trypomastigotes are not immunoreactive with the...humoral immune response of an infected host and that suppression of parasitemias in chronic Chagas ’ disease is probably a function of the cell immune system of the host. (Author)

  17. High precision prism scanning system

    NASA Astrophysics Data System (ADS)

    García-Torales, G.; Flores, J. L.; Muñoz, Roberto X.

    2007-03-01

    Risley prisms are commonly used in continuous scanning manner. Each prism is capable of rotating separately about a common axis at different speeds. Scanning patterns are determined by the ratios of the wedge angles, the speed and direction of rotation of both prisms. The use of this system is conceptually simple. However, mechanical action in most applications becomes a challenge often solved by the design of complex control algorithms. We propose an electronic servomotor system that controls incremental and continuous rotations of the prisms wedges by means of an auto-tuning PID control using a Adaline Neural Network Algorithm, NNA.

  18. Compound prism design principles, II: triplet and Janssen prisms.

    PubMed

    Hagen, Nathan; Tkaczyk, Tomasz S

    2011-09-01

    Continuing the work of the first paper in this series [Appl. Opt. 50, 4998-5011 (2011)], we extend our design methods to compound prisms composed of three independent elements. The increased degrees of freedom of these asymmetric prisms allow designers to achieve greatly improved dispersion linearity. They also, however, require a more careful tailoring of the merit function to achieve design targets, and so we present several new operands for manipulating the compound prisms' design algorithm. We show that with asymmetric triplet prisms, one can linearize the angular dispersion such that the spectral sampling rate varies by no more than 4% across the entire visible spectral range. Doing this, however, requires large prisms and causes beam compression. By adding a beam compression penalty to the merit function, we show that one can compromise between dispersion linearity and beam compression in order to produce practical systems. For prisms that do not deviate the beam, we show that Janssen prisms provide a form that maintains the degrees of freedom of the triplet and that are capable of up to 32° of dispersion across the visible spectral range. Finally, in order to showcase some of the design flexibility of three-element prisms, we also show how to design for higher-order spectral dispersion to create a two-dimensional spectrum.

  19. Through a prism darkly: re-evaluating prisms and neglect.

    PubMed

    Striemer, Christopher L; Danckert, James A

    2010-07-01

    Many studies have demonstrated that prism adaptation can reduce several symptoms of visual neglect: a disorder in which patients fail to respond to information in contralesional space. The dominant framework to explain these effects proposes that prisms influence higher order visuospatial processes by acting on brain circuits that control spatial attention and perception. However, studies that have directly examined the influence of prisms on perceptual biases inherent to neglect have revealed very few beneficial effects. We propose an alternative explanation whereby many of the beneficial effects of prisms arise via the influence of adaptation on circuits in the dorsal visual stream controlling attention and visuomotor behaviors. We further argue that prisms have little influence on the pervasive perceptual biases that characterize neglect. Crown Copyright (c) 2010. Published by Elsevier Ltd. All rights reserved.

  20. Calibration of the Wedge Prism

    Treesearch

    Charles B. Briscoe

    1957-01-01

    Since the introduction of plotless cruising in this country by Grosenbaugh and the later suggestion of using a wedge prism as an angle gauge by Bruce this method of determining basal area has been widely adopted in the South. One of the factors contributing to the occasionally unsatisfactory results obtained is failure to calibrate the prism used. As noted by Bruce the...

  1. Multiplexing Prisms for Field Expansion.

    PubMed

    Peli, Eli; Jung, Jae-Hyun

    2017-08-01

    Prisms used for field expansion are limited by the optical scotoma at a prism apex (apical scotoma). For a patient with two functioning eyes, fitting prisms unilaterally allows the other eye to compensate for the apical scotoma. A monocular patient's field loss cannot be expanded with a conventional or Fresnel prism because of the apical scotoma. A newly invented optical device, the multiplexing prism (MxP), was developed to overcome the apical scotoma limitation in monocular field expansion. A Fresnel-prism-like device with alternating prism and flat elements superimposes shifted and see-through views, thus creating the (monocular) visual confusion required for field expansion and eliminating the apical scotoma. Several implementations are demonstrated and preliminarily evaluated for different monocular conditions with visual field loss. The field expansion of the MxP is compared with the effect of conventional prisms using calculated and measured perimetry. Field expansion without apical scotomas is shown to be effective for monocular patients with hemianopia or constricted peripheral field. The MxPs are shown to increase the nasal field for a patient with only one eye and for patients with bitemporal hemianopia. The MxPs placed at the far temporal field are shown to expand the normal visual field. The ability to control the contrast ratio between the two images is verified. A novel optical device is demonstrated to have the potential for field expansion technology in a variety of conditions. The devices may be inexpensive and can be constructed in a cosmetically acceptable format.

  2. Multibeam collimator uses prism stack

    NASA Technical Reports Server (NTRS)

    Minott, P. O.

    1981-01-01

    Optical instrument creates many divergent light beams for surveying and machine element alignment applications. Angles and refractive indices of stack of prisms are selected to divert incoming laser beam by small increments, different for each prism. Angles of emerging beams thus differ by small, precisely-controlled amounts. Instrument is nearly immune to vibration, changes in gravitational force, temperature variations, and mechanical distortion.

  3. Compound prism design principles, II: triplet and Janssen prisms

    PubMed Central

    Hagen, Nathan; Tkaczyk, Tomasz S.

    2011-01-01

    Continuing the work of the first paper in this series [Appl. Opt. 50, 4998–5011 (2011)], we extend our design methods to compound prisms composed of three independent elements. The increased degrees of freedom of these asymmetric prisms allow designers to achieve greatly improved dispersion linearity. They also, however, require a more careful tailoring of the merit function to achieve design targets, and so we present several new operands for manipulating the compound prisms’ design algorithm. We show that with asymmetric triplet prisms, one can linearize the angular dispersion such that the spectral sampling rate varies by no more than 4% across the entire visible spectral range. Doing this, however, requires large prisms and causes beam compression. By adding a beam compression penalty to the merit function, we show that one can compromise between dispersion linearity and beam compression in order to produce practical systems. For prisms that do not deviate the beam, we show that Janssen prisms provide a form that maintains the degrees of freedom of the triplet and that are capable of up to 32° of dispersion across the visible spectral range. Finally, in order to showcase some of the design flexibility of three-element prisms, we also show how to design for higher-order spectral dispersion to create a two-dimensional spectrum. PMID:22423146

  4. Compound prism design principles, I

    PubMed Central

    Hagen, Nathan; Tkaczyk, Tomasz S.

    2011-01-01

    Prisms have been needlessly neglected as components used in modern optical design. In optical throughput, stray light, flexibility, and in their ability to be used in direct-view geometry, they excel over gratings. Here we show that even their well-known weak dispersion relative to gratings has been overrated by designing doublet and double Amici direct-vision compound prisms that have 14° and 23° of dispersion across the visible spectrum, equivalent to 800 and 1300 lines/mm gratings. By taking advantage of the multiple degrees of freedom available in a compound prism design, we also show prisms whose angular dispersion shows improved linearity in wavelength. In order to achieve these designs, we exploit the well-behaved nature of prism design space to write customized algorithms that optimize directly in the nonlinear design space. Using these algorithms, we showcase a number of prism designs that illustrate a performance and flexibility that goes beyond what has often been considered possible with prisms. PMID:22423145

  5. Bathymetry Beneath Abbot Ice Shelf, West Antarctica, From Inversion Of Icebridge Gravity Data: Glaciological And Tectonic Implications

    NASA Astrophysics Data System (ADS)

    Cochran, J. R.; Tinto, K. J.; Bell, R. E.

    2012-12-01

    The Abbot Ice Shelf, with a surface area of just over 30,000 km2, extends for about 400 km along the Eights Coast of West Antarctica between 103°W and 89°W. Thurston Island forms the seaward side of the western portion of the ice shelf, while the eastern portion opens onto the Bellingshausen Sea. The very western edge of the ice shelf opens into the Amundsen Embayment. Operation IceBridge radar data show that the ice thickness over most of the ice shelf varies from 180-350 m. Numerous islands and ice rises imply a complex bathymetry beneath the ice shelf. NASA's Operation IceBridge obtained ten north-south low-altitude airborne geophysical profiles across Abbot Ice Shelf and an east-west line along the ice shelf during the 2009 OIB Antarctic campaign. We inverted the gravity data from these flights to obtain the bathymetry and water cavity geometry on a set of cross sections. Coincident radar data provided control on ice thickness and the location of the bed in grounded regions. The inversion shows that the ice shelf is underlain by a series of east-west trending, apparently fault-bounded, basins. The individual basins are less than 75 km long and vary from 15 to 35 km wide. The ice shelf is pinned on the rift shoulders and intra-rift highs, which results in low (50-150 m/yr) flow rates compared to other ice shelves. The basins do not extend the entire length of the ice shelf but are discontinuous or offset along accommodation zones. This complex geometry may inhibits circulation in the water cavity beneath the ice shelf and contribute to its stability. The structure beneath the Abbot Ice Shelf indicates minor crustal extension. The extension may be related to Latest Cretaceous intra-plate deformation or the presence of a distributed southern plate boundary of the Bellingshausen microplate that is thought to have been active from about 79 Ma to 61 Ma.

  6. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior chamber...

  7. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior chamber...

  8. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior chamber...

  9. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior chamber...

  10. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior chamber...

  11. into the accretionary prism

    NASA Astrophysics Data System (ADS)

    Okamoto, Atsushi; Musya, Michimasa; Hashimoto, Yoshitaka; Tsuchiya, Noriyoshi

    2014-12-01

    Carbon dioxide and methane are major components in geofluids; however, there is little evidence showing how C-H-O fluids evolve in a subduction zone. We investigated fluid inclusions in quartz veins from the Eocene-Oligocene Shimanto belt (Murotohanto subbelt) on Muroto Peninsula, SW Japan using microthermometry and laser Raman spectroscopy. Quartz veins that cut the cleavage of the host rocks in the Murotohanto subbelt contain one-phase carbonic inclusions (CH4) and two-phase aqueous inclusions (CH4 ± CO2 vapor and H2O liquid). The vapor in the two-phase inclusions is essentially CH4 in the northern part of the belt and a CO2-CH4 mixture in the southern part; values of [InlineEquation not available: see fulltext.] (=CO2 / (CO2 + CH4)) vary from 0 to 0.9. Within a single CO2-bearing vein, [InlineEquation not available: see fulltext.] values decrease from the vein wall ([InlineEquation not available: see fulltext.] = 0.5 to 0.9) to the vein center ([InlineEquation not available: see fulltext.] = 0), and the homogenization temperature increases from approximately 180°C to 240°C-250°C, indicating a transition of the carbonic species from CO2-CH4 to CH4 during vein formation. CO2-dominant fluids are rare in most accretionary prisms formed under low-grade metamorphic conditions, and the generation of CO2 cannot be explained by diagenesis of organic matter in sediments under the P-T conditions of formation of the CO2-bearing veins (235°C to 245°C, 165 to 200 MPa). The CO2 fluids are distributed preferentially near an out-of-sequence thrust that brings the Murotohanto subbelt into contact with the late Oligocene-early Miocene Nabae subbelt and its many volcanic and intrusive rocks. We therefore suggest that the CO2 fluids were generated in association with near-trench magmatism during the middle Miocene and that the fluids were injected and mixed with the CH4 pore fluids of the sediments in the accretionary prism.

  12. Prism beamswitch for radio telescopes.

    PubMed

    Payne, J M; Ulich, B L

    1978-12-01

    A dielectric prism and switching mechanism have been constructed for beamswitching a Cassegrain radio telescope. Spatially extended radio sources may be mapped without significant confusion utilizing the sensitivity and stability inherent in the conventional Dicke radiometer.

  13. Prism Window for Optical Alignment

    NASA Technical Reports Server (NTRS)

    Tang, Hong

    2008-01-01

    A prism window has been devised for use, with an autocollimator, in aligning optical components that are (1) required to be oriented parallel to each other and/or at a specified angle of incidence with respect to a common optical path and (2) mounted at different positions along the common optical path. The prism window can also be used to align a single optical component at a specified angle of incidence. Prism windows could be generally useful for orienting optical components in manufacture of optical instruments. "Prism window" denotes an application-specific unit comprising two beam-splitter windows that are bonded together at an angle chosen to obtain the specified angle of incidence.

  14. The PRISM concept

    SciTech Connect

    Circeo, L.J. Jr.; Jacobs, G.K.; Camacho, S.L.; Tixier, J.S.

    1994-09-01

    Contaminated soils and buried wastes represent one of the most widespread and costly remediation problems in the United States and other developed countries around the world. This concept of in situ remediation using a plasma arc torch should be directly applicable to many of the contaminated soil remediation needs described the DOE, EPA, and DoD. Plasma Remediation of In Situ Materials (PRISM) could provide a highly efficient, cost-effective, reliable and controllable technique to selectively melt and vitrify any contaminated/buried volume of soils, materials, or objects at any depth underground. If necessary, it could pinpoint underground objects such as buried drums for selective remediation. Plasma arc technology was developed over 30 years ago by NASA for the US space program to simulate reentry temperatures on heat shields. Only recently has this technology begun to emerge as a commercial tool in several industries such as steelmaking, metallurgy, precious metal recovery, and waste disposal. Conceptually, a plasma torch could be used on the ground surface or lowered to the bottom of a small diameter, cased borehole. By raising and operating the torch at progressively higher levels a column of contaminated material would be vitrified and converted into an environmentally safe, glassy residue, highly resistant to leaching. With proper borehole spacing the vitrified columns could be coalesced together to form a contiguous, homogeneous mass of vitrified material which is environmentally safe and highly resistant to leaching.

  15. The history of Chagas disease

    PubMed Central

    2014-01-01

    The ancestor of Trypanosome cruzi was probably introduced to South American via bats approximately 7-10 million years ago. When the first humans arrived in the New World, a sylvatic cycle of Chagas disease was then already well established. Paleoparasitological data suggests that human American trypanosomiasis originated in the Andean area when people founded the first settlements in the coastal region of the Atacama Desert. Identification of T. cruzi as the etiological agent and triatome bugs as the transmission vector of Chagas disease occurred within a few years at the beginning of the 20th century. History also teaches us that human activity leading to environmental changes, in particular deforestation, is the main cause for the spread of Chagas disease. Recently, migration of T. cruzi-infected patients has led to a distribution of Chagas disease from Latin America to non-endemic countries in Europe, North America and western Pacific region. PMID:25011546

  16. [Chagas disease in Brazil].

    PubMed

    Vinhaes, M C; Dias, J C

    2000-01-01

    This article presents the current situation for Chagas disease vectors in Brazil, based on data from the Brazilian National Health Foundation (FNS). Over the course of the last 20 years, continuous chemical control has resulted in a clear reduction of triatomine densities and Trypanosoma cruzi in Brazilian dwellings. Results have been particularly promising in relation to Triatoma infestans and Panstrongylus megistus, considered the most important species in the past. In parallel, data from school serological surveys, hospitalized patients, and mortality records show an important decrease in the disease. Nevertheless, some areas of the Brazilian Northeast and some residual foci of Triatoma infestans and Panstrongylus megistus remain as major challenges for public health authorities, requiring effective epidemiological surveillance. States and municipalities are required to assume this task at present, as the traditional Brazilian National Health Foundation is undergoing decentralization.

  17. Supplement Analysis for the Wildlife Mitigation Program EIS (DOE/EIS-0246/SA-27) - Abbot Creek Fish Barrier Project (Hungry Horse Mitigation / Habitat Improvements)

    SciTech Connect

    Yarde, Richard

    2002-06-28

    BPA proposes to fund a fishery enhancement project where a fish passage barrier will be installed in Abbot Creek to remove introduced rainbow trout and prevent hybridization with westslope cutthroat trout. Montana Fish, Wildlife & Parks (MFWP) will operate a fish trap downstream of the barrier for 6-10 consecutive years to manually remove the rainbow trout and hybrid spawners from the population. Removal of rainbow trout and hybrids from the stream will eradicate the existing hybrid population spawning in Abbot Creek and ultimately reduce the threat of hybridization in the Flathead River system. Pending completion of a successful disease screening and authorization from MFWP Fish Health Committee, live fish captured in the fish trap will be transported to a nearby close-basin lake for use in MFWP’s Urban Fishing Program.

  18. Chagas' disease after bone marrow transplantation.

    PubMed

    Altclas, J; Jaimovich, G; Milovic, V; Klein, F; Feldman, L

    1996-08-01

    Chagas' disease is caused by Trypanosoma cruzi. It is endemic in Latin America where 16 to 18 million people are infected. Immunocompromised patients such as BMT recipients are at risk of Chagas' disease either due to reactivation or transfusion. We report a case of acute Chagas' disease in the setting of BMT.

  19. Acute Chagas Disease in a Returning Traveler

    PubMed Central

    Carter, Yvonne L.; Juliano, Jonathan J.; Montgomery, Susan P.; Qvarnstrom, Yvonne

    2012-01-01

    Acute Chagas disease is rarely recognized, and the risk for acquiring the disease is undefined in travelers to Central America. We describe a case of acute Chagas disease in a traveler to Costa Rica and highlight the need for increased awareness of this infection in travelers to Chagas-endemic areas. PMID:23091192

  20. Laser system with partitioned prism

    SciTech Connect

    Nettleton, J. E.; Barr, D. N.

    1985-03-26

    An array of optical frequency-sensitive elements such as diffraction gratings or interference filters are arranged in a row, and the optical path of the laser cavity can be directed to include one of these elements. A partitioned optical prism consisting of a triangular portion and one or more paralleogramatic portions are used to direct the path. Between the portions are piezoelectric elements which, when energized, expand to provide an air gap between the portions and to allow total reflection of an optical ray at the surface of the prism next to the gap.

  1. Control of Chagas disease.

    PubMed

    Yamagata, Yoichi; Nakagawa, Jun

    2006-01-01

    The Southern Cone Initiative (Iniciativa de Salud del Cono Sur, INCOSUR) to control domestic transmission of Trypanosoma cruzi is a substantial achievement based on the enthusiasm of the scientific community, effective strategies, leadership, and cost-effectiveness. INCOSUR triggered the launch of other regional initiatives in Central America and in the Andean and Amazon regions, which have all made progress. The Central American Initiative targeted the elimination of an imported triatomine bug (Rhodnius prolixus) and the control of a widespread native species (Triatoma dimidiata), and faced constraints such as a small scientific community, the difficulty in controlling a native species, and a vector control programme that had fragmented under a decentralized health system. International organizations such as the Japan International Cooperation Agency (JICA) have played an important role in bridging the gaps between fragmented organizational resources. Guatemala achieved virtual elimination of R. prolixus and ;reduction of Tri. Dimidiata and El Salvador and Honduras revitalized their national programmes. The programme also revealed new challenges. Tri. dimidiata control needs to cover a large geographic area efficiently with stratification, quality control, community mobilization, and information management. Stakeholders such as the National Chagas Program, the local health system and their communities, as well as local government must share responsibilities to continue comprehensive vector control.

  2. Chagas Heart Disease: An Update.

    PubMed

    Malik, Lindsey H; Singh, Gagan D; Amsterdam, Ezra A

    2015-11-01

    Chagas disease, also known as American trypanosomiasis, results from infection by the protozoan Trypanosoma cruzi, and is a major cause of cardiac disease worldwide. Until recently, Chagas disease was confined to those areas of South and Central America where Trypanosoma cruzi is endemic. With the migration of infected individuals, however, the disease has spread, and it is estimated that 6-7 million people worldwide are infected. In the US alone, more than 7 million people from Trypanosoma cruzi-endemic countries became legal US residents by the turn of the century, resulting in a surge of Chagas disease in this country. According to preliminary estimates, the US now ranks seventh in the Western Hemisphere in number of individuals infected with Trypanosoma cruzi, and the disease has become a major public health concern due to limited awareness in the medical community. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Rotatable prism for pan and tilt

    NASA Technical Reports Server (NTRS)

    Ball, W. B.

    1980-01-01

    Compact, inexpensive, motor-driven prisms change field of view of TV camera. Camera and prism rotate about lens axis to produce pan effect. Rotating prism around axis parallel to lens produces tilt. Size of drive unit and required clearance are little more than size of camera.

  4. Heart Transplantation for Chagas Cardiomyopathy.

    PubMed

    Benatti, Rodolfo D; Oliveira, Guilherme H; Bacal, Fernando

    2017-06-01

    Chagas cardiomyopathy (CC) is one of the chronic manifestations of Trypanosoma cruzi (T. cruzi) infection and is a major public health disease in Latin America. Since it is a chronic systemic infection, Chagas disease was long considered a potential contraindication for transplantation because of the risk of recurrence with immunosuppression. However, early South American experience in the 1980's established the feasibility of heart transplantation (HT) in patients with Chagas disease. Indeed, the first cardiac transplant for a recipient with CC was performed in 1985 in Brazil. Chagas etiology of heart failure has become the third most common indication for HT in South America. T. cruzi reactivation post-transplant is a common issue that requires prophylactic surveillance but responds well to appropriate therapy. Chagas reactivation has been associated with the potency of the immunosuppressive protocol and occurs more frequently after rejection episodes. Yet, many important questions regarding the management of Chagas HT candidates and recipients remain unanswered. For example, biventricular systolic failure is frequent in end-stage CC, but its impact on the modality of mechanical circulatory bridging has not been described. Also, there is no consensus regarding the most adequate immunosuppressive regimen that balances the risk of graft rejection and disease reactivation. The real efficacy and safety of HT for end-stage CC will only be appreciated when a Latin American transplant registry is established. This review covers the current state of the art of HT for CC. Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  5. Understanding by Looking Through Prisms.

    PubMed

    Ortuno, Lila; Florczak, Kristine L

    2017-04-01

    The authors of this column explore the transformational journey of a nursing student pursuing a graduate degree through the prisms of ethics, aesthetics, and nursing theory. The wisdom and insights gained contribute to an ever-changing worldview of humans and living experiences.

  6. Preserving with Prisms: Producing Nets

    ERIC Educational Resources Information Center

    Prummer, Kathy E.; Amador, Julie M.; Wallin, Abraham J.

    2016-01-01

    Two mathematics teachers in a small rural school decided to create a task that would engage seventh graders. The goal of the real-world activity was to help students develop geometric and spatial reasoning and to support their understanding of volume of rectangular prisms. The impetus for the task came from the teachers' desire to engage students…

  7. Preserving with Prisms: Producing Nets

    ERIC Educational Resources Information Center

    Prummer, Kathy E.; Amador, Julie M.; Wallin, Abraham J.

    2016-01-01

    Two mathematics teachers in a small rural school decided to create a task that would engage seventh graders. The goal of the real-world activity was to help students develop geometric and spatial reasoning and to support their understanding of volume of rectangular prisms. The impetus for the task came from the teachers' desire to engage students…

  8. Transfusion-transmitted Chagas' disease.

    PubMed

    Wendel, S

    1998-11-01

    Transfusion-transmitted Chagas' disease has been recognized since 1952. Until recently, no cases were reported outside of Latin America. However, emigration during the past 20 years expanded its transfusional geographic borders to North America. Trypanosoma cruzi-infected donors usually are asymptomatic, often for a lifetime. This situation complicates donor screening, particularly in regions where blood bank personnel are not familiar with the risk factors and natural history of this transfusion-transmitted infection. This review addresses the main aspects of epidemiology, risks of infection, clinical symptoms in donors and recipients, preventive measures, and blood donor screening to prevent transfusion-transmitted Chagas' disease.

  9. Thin pseudotachylytes in faults of the Mt. Abbot quadrangle, Sierra Nevada: Physical constraints for small seismic slip events

    NASA Astrophysics Data System (ADS)

    Griffith, W. Ashley; Di Toro, Giulio; Pennacchioni, Giorgio; Pollard, David D.

    2008-09-01

    We document the occurrence of pseudotachylyte (solidified melt produced during seismic slip) along strike-slip faults in the Lake Edison granodiorite of the Mt. Abbot quadrangle, Sierra Nevada, California and provide constraints on ambient conditions during seismic faulting. The pseudotachylytes are less than 0.3 mm thick and are found in faults typically up to 1 cm in thickness. Total measured left-lateral offset along sampled faults is approximately 20 cm. Field and microstructural evidence indicate that the faults exploited pre-existing mineralized joints and show the following overprinting structures (with inferred ambient temperatures): mylonites are more or less coeval with quartz veins (>400 °C), cataclasites and pseudotachylytes (˜250 °C) more or less coeval with epidote veins, and zeolite veins (<200 °C). Based on observations of the microstructural textures of faults combined with theoretical heat transfer and energy budget calculations, we suggest that only a fraction (<30%) of the total offset was associated with seismic slip (i.e. pseudotachylyte). The presence of pseudotachylyte in sub-millimeter thick zones lends support for the concept of extreme shear localization during seismic slip. The elusive nature of these pseudotachylytes demonstrates that observations in outcrop and optical microscope are not sufficient to rule out frictional melting as a consequence of seismic slip in similar fault rocks.

  10. A Liquid Prism for Refractive Index Studies

    NASA Astrophysics Data System (ADS)

    Edmiston, Michael D.

    2001-11-01

    A hollow glass prism filled with liquid becomes a "liquid prism". A simple method for constructing hollow glass prisms is presented. A method is given for a demonstration that uses the liquid prism with a laser or laser pointer so the audience can observe differences in refractive index for various liquids. The demonstration provides a quick and easy determination of the sugar content of soft drinks and juices. The prism makes it easy to determine a numerical value for the refractive index of a liquid.

  11. Diffractively corrected counter-rotating Risley prisms.

    PubMed

    Nie, Xin; Yang, Hongfang; Xue, Changxi

    2015-12-10

    Using the vector refraction equation and the vector diffraction equation, we obtain the expressions of the direction cosines of the refractive rays for the two wedge prisms, and the direction cosines of the diffractive rays for two wedge grisms, in which diffractive gratings were etched into the prism faces to correct the chromatic aberrations. A mathematical model between the two vector equations is proposed to compare the difference angle chromatic aberrations when the Risley prisms/grisms are rotating at different angles. We conclude that the use of diffractively corrected prisms offers a new method to correct chromatic aberrations in Risley prisms.

  12. PRISM Polarimetry of Massive Stars

    NASA Astrophysics Data System (ADS)

    Kerkstra, Brennan; Lomax, Jamie R.; Bjorkman, Karen S.; Bjorkman, Jon Eric; Skiff, Brian; Covey, Kevin R.; Wisniewski, John P.

    2016-01-01

    We present the early results from our long-term, multi-epoch filter polarization survey of massive stars in and around young Galactic clusters. These BVRI polarization data were obtained using the PRISM instrument mounted on the 1.8m Perkins Telescope at Lowell Observatory. We first detail the creation of our new semi-automated polarization data reduction pipeline that we developed to process these data. Next, we present our analysis of the instrumental polarization properties of the PRISM instrument, via observations of polarized and unpolarized standard stars. Finally, we present early results on the total and intrinsic polarization behavior of several isolated, previously suggested classical Be stars, and discuss these results in the context of the larger project.BK acknowledges support from a NSF/REU at the University of Oklahoma. This program was also supported by NSF-AST 11411563, 1412110, and 1412135.

  13. Three timescales in prism adaptation.

    PubMed

    Inoue, Masato; Uchimura, Motoaki; Karibe, Ayaka; O'Shea, Jacinta; Rossetti, Yves; Kitazawa, Shigeru

    2015-01-01

    It has been proposed that motor adaptation depends on at least two learning systems, one that learns fast but with poor retention and another that learns slowly but with better retention (Smith MA, Ghazizadeh A, Shadmehr R. PLoS Biol 4: e179, 2006). This two-state model has been shown to account for a range of behavior in the force field adaptation task. In the present study, we examined whether such a two-state model could also account for behavior arising from adaptation to a prismatic displacement of the visual field. We first confirmed that an "adaptation rebound," a critical prediction of the two-state model, occurred when visual feedback was deprived after an adaptation-extinction episode. We then examined the speed of decay of the prism aftereffect (without any visual feedback) after repetitions of 30, 150, and 500 trials of prism exposure. The speed of decay decreased with the number of exposure trials, a phenomenon that was best explained by assuming an "ultraslow" system, in addition to the fast and slow systems. Finally, we compared retention of aftereffects 24 h after 150 or 500 trials of exposure: retention was significantly greater after 500 than 150 trials. This difference in retention could not be explained by the two-state model but was well explained by the three-state model as arising from the difference in the amount of adaptation of the "ultraslow process." These results suggest that there are not only fast and slow systems but also an ultraslow learning system in prism adaptation that is activated by prolonged prism exposure of 150-500 trials.

  14. PRISM3/GISS Topographic Reconstruction

    USGS Publications Warehouse

    Sohl, Linda E.; Chandler, Mark A.; Schmunk, Robert B.; Mankoff, Ken; Jonas, Jeffrey A.; Foley, Kevin M.; Dowsett, Harry J.

    2009-01-01

    The PRISM3/GISS topographic reconstruction is one of the global data sets incorporated into a new reconstruction for the mid-Piacenzian warm interval of the Pliocene, at about 3.3 to 3.0 Ma. The PRISM3/GISS topography-gridded data set is a digitization of a graphical reconstruction, provided at 2 deg x 2 deg resolution and based on updated paleoaltimetry data and a refined land/ocean mask. Mid-Piacenzian topography as shown in this data set is generally quite similar to modern topography, with three notable differences: (1) the coastline as shown is 25 meters higher than modern sea level, reflecting the hypothesized reduction in ice sheet volume; (2) Hudson Bay is filled in to low elevation, in the absence of evidence for submergence at that time; and (3) the West Antarctic ice sheet is absent, permitting open seaways to exist in Ellsworth and Marie Byrd Lands. Two alternate ice sheet configurations with corresponding vegetation schemes are available; one is a minor modification of the PRISM2 ice reconstruction, and one is derived from the British Antarctic Survey Ice Sheet Model (BAS ISM).

  15. Contamination of disposable tonometer prisms during tonometry.

    PubMed

    Rajak, S N; Paul, J; Sharma, V; Vickers, S

    2006-03-01

    Due to the theoretical possibility of prion transmission in applanation tonometry, many ophthalmological units in the United Kingdom now use disposable tonometer prisms. We have investigated the potential for bacterial and viral transmission from the health practitioner to the patient via disposable prisms. All staff who perform applanation tonometry at the Sussex Eye Hospital (SEH) received a questionnaire to evaluate if the applanating face of the prism is touched during tonometry and the ease of use of the disposable prism compared to the reusable prisms that were previously used. We then cultured prisms handled by a random sample of staff members for common bacteria. Finally, we constructed a model to investigate the possibility of interpatient adenoviral transmission via disposable tonometer prisms. The questionnaire revealed that almost 50% of the staff admit to touching the applanating face of the tonometer prism prior to applanation. Cultures of the prisms grew a range of bacteria including Staphylococcus epidermidis, Staphylococcus aureus, and Bacillus species. The viral model suggested that adenovirus could be transmitted by applanation tonometry. The use of disposable prisms for applanation tonometry may reduce the risk of prion transmission but is not bacteriologically or virologically aseptic. This is a potential infection risk to patients.

  16. Comparison of near fusional vergence ranges with rotary prisms and with prism bars.

    PubMed

    Goss, David A; Becker, Emily

    2011-02-01

    Common methods for determination of fusional vergence ranges make use of rotary prisms in the phoropter or prism bars out of the phoropter. This study compared near fusional vergence ranges with rotary prisms with those with prism bars. Fifty young adults served as subjects. Odd-numbered subjects had rotary prism vergences performed before prism bar vergences. For even-numbered subjects, prism bar vergences were done first. Base-in (BI) vergences were done before base-out (BO) vergences with both rotary prisms and prism bars. A coefficient of agreement was calculated by multiplying the standard deviation of the individual subject differences between rotary prisms and prism bars by 1.96, to approximate the range within which the 2 tests would agree 95% of the time. The lowest coefficient of agreement was 7.3Δ for the BI recovery. The others were high, ranging from 15.4Δ for the BO recovery to 19.5Δ for the BO break. Fusional vergence ranges determined by prism bars out of the phoropter cannot be used interchangeably with those determined by phoropter rotary prisms for the purpose of follow-up on individual patients or for the purpose of comparison with norms. Copyright © 2010 American Optometric Association. Published by Elsevier Inc. All rights reserved.

  17. Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica

    PubMed Central

    Cochran, James R; Tinto, Kirsty J; Bell, Robin E

    2015-01-01

    Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β, of 1.5–1.7 with 80–100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts. Key Points: Abbot Ice Shelf is underlain by E-W rift basins created at ∼90 Ma Amundsen shelf shaped by subsidence, sedimentation, and passage of the ice sheet Bellingshausen plate boundary is located near the base of continental slope and rise PMID:26709352

  18. Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica.

    PubMed

    Cochran, James R; Tinto, Kirsty J; Bell, Robin E

    2015-05-01

    Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β, of 1.5-1.7 with 80-100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts. Abbot Ice Shelf is underlain by E-W rift basins created at ∼90 Ma Amundsen shelf shaped by subsidence, sedimentation, and passage of the ice sheet Bellingshausen plate boundary is located near the base of continental slope and rise.

  19. Inverse solutions for tilting orthogonal double prisms.

    PubMed

    Li, Anhu; Ding, Ye; Bian, Yongming; Liu, Liren

    2014-06-10

    An analytical reverse solution and actual examples are given to show how to direct a laser beam from a pair of orthogonal prisms to given targets in free space. Considering the influences of double-prism structural parameters, a lookup table method to seek the numerical reverse solution of each prism's tilting angle is also proposed for steering the double-prism orientation to track a target position located in the near field. Some case studies, as well as a specified elliptical target trajectory scanned by the cam-based driving double prisms, exhibit the significant application values of the theoretical derivation. The analytic reverse and numerical solutions can be generalized to investigate the synthesis of scanning patterns and the controlling strategy of double-prism tilting motion, the potentials of which can be explored to perform the orientation and position tracking functions in applications of precision engineering fields.

  20. Ray tracing in Rochon prisms with absorption.

    PubMed

    Lv, Meibo; Wang, Pei

    2017-06-26

    We theoretically analyze inhomogeneous plane waves propagating in a Rochon prism made from uniaxial absorbing material. Expressions for the propagation and attenuation directions of the ordinary and the extraordinary waves in the lossy Rochon prism are derived by complex ray-tracing method. As an application, the propagation characteristic of the inhomogeneous plane waves within the lossy Rochon prisms at normal incidence are analyzed and discussed.

  1. [Globalization, inequity and Chagas disease].

    PubMed

    Dias, João Carlos Pinto

    2007-01-01

    Chagas disease (American trypanosomiasis) bears a close relationship to multiple social and political aspects involving issues of globalization and inequity. Such relations concern the process of disease production and control in parallel with medical management. Despite the poverty in Latin America and various problems related to inequities and globalization, Chagas disease has been controlled in several areas, a fact that reinforces the countries' self-reliance. Several problems and challenges related to the disease can be expected in the future, mainly concerning medical care for already infected individuals and the sustainability of effective epidemiological surveillance. Both points depend heavily on improved performance by the national health systems, principally in terms of their efficiency and their capacity to overcome inequity. A particularly important role has been attributed to the Latin American scientific and academic community in the implementation and sustainability of efficient control policies. Control activities have now evolved towards internationally shared initiatives, a major new stride forward in the region's political context.

  2. Duodenogastric reflux in Chagas' disease

    SciTech Connect

    Troncon, L.E.; Rezende Filho, J.; Iazigi, N.

    1988-10-01

    Increased duodenogastric reflux has been recognized as a cause of gastric mucosa damage. The frequent finding of bile-stained gastric juice and a suggested higher frequency of lesions of the gastric mucosa in patients with Chagas' disease, which is characterized by a marked reduction of myenteric neurons, suggest that impairment of intrinsic innervation of the gut might be associated with increased duodenogastric reflux. Duodenogastric bile reflux was quantified after intravenous injection of 99mtechnetium-HIDA, in 18 patients with chronic Chagas' disease, 12 controls, and 7 patients with Billroth II gastrectomy. All but one of the chagasic patients were submitted to upper digestive tract endoscopy. High reflux values (greater than or equal to 10%) were detected both in chagasic patients and in the controls, but the values for both groups were significantly lower (P less than 0.01) than those obtained for Billroth II patients (median: 55.79%; range: 12.58-87.22%). Reflux values tended to be higher in the Chagas' disease group (median: 8.20%; range: 0.0-29.40%) than in the control group (median: 3.20%; range: 0.0-30.64%), with no statistical difference between the two groups (P greater than 0.10). Chronic gastritis was detected by endoscopy in 12 chagasic patients, benign gastric ulcer in 2 patients, and a pool of bile in the stomach in 11 patients. However, neither the occurrence of gastric lesions nor the finding of bile-stained gastric juice was associated with high reflux values after (99mTc)HIDA injection. This study suggests that lesions of the intramural nervous system of the gut in Chagas' disease do not appear to be associated with abnormally increased duodenogastric reflux.

  3. Heterologous Infection During Chagas' Disease

    NASA Astrophysics Data System (ADS)

    Sibona, G. J.; Condat, C. A.; Cossi Isasi, S.

    2007-05-01

    Human populations are often infected with more than one parasite strain. This is frequently the case with ChagasŠ disease, which is endemic to large regions of Latin America. In the present work we study the dynamics of the heterologous infection for this disease, using a model for the interaction between the trypanosoma cruzi parasite and the immune system. We find the dependence of the nature of the post-acute stage on the parameters characterizing the inoculated infectious strains.

  4. Cell therapies for Chagas disease.

    PubMed

    Carvalho, Adriana Bastos; Goldenberg, Regina Coeli Dos Santos; Campos de Carvalho, Antonio Carlos

    2017-09-05

    In this review of cell therapies in Chagas disease, we cover aspects related to the disease, its treatment and world demographics, before proceeding to describe the preclinical and clinical trials performed using cell therapies in the search for an alternative therapy for the most severe and lethal form of this disease, chronic chagasic cardiomyopathy. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  5. Error and adjustment of reflecting prisms

    NASA Astrophysics Data System (ADS)

    Mao, Wenwei

    1997-12-01

    A manufacturing error in the orientation of the working planes of a reflecting prism, such as an angle error or an edge error, will cause the optical axis to deviate and the image to lean. So does an adjustment (position error) of a reflecting prism. A universal method to be used to calculate the optical axis deviation and the image lean caused by the manufacturing error of a reflecting prism is presented. It is suited to all types of reflecting prisms. A means to offset the position error against the manufacturing error of a reflecting prism and the changes of image orientation is discussed. For the calculation to be feasible, a surface named the 'separating surface' is introduced just in front of the real exit face of a real prism. It is the image of the entrance face formed by all reflecting surfaces of the real prism. It can be used to separate the image orientation change caused by the error of the prism's reflecting surfaces from the image orientation change caused by the error of the prism's refracting surface. Based on ray tracing, a set of simple and explicit formulas of the optical axis deviation and the image lean for a general optical wedge is derived.

  6. Computational economy improvements in PRISM

    SciTech Connect

    Tonse, Shaheen R.; Brown, Nancy J.

    2003-01-29

    The PRISM piecewise solution mapping procedure, in which the solution of the chemical kinetic ODE system is parameterized with quadratic polynomials, is applied to CFD simulations of H{sub 2}+air combustion. Initial cost of polynomial construction is expensive, but it is recouped as the polynomial is reused. We present two methods that help us to parameterize only in places that will ultimately have high reuse. We also implement non-orthogonal Gosset factorial designs, that reduce polynomial construction costs by a factor of two over previously used orthogonal factorial designs.

  7. [Clinical profile of Chagas and non-Chagas' disease patients with cardiac pacemaker].

    PubMed

    Rincon, Leonor Garcia; Rocha, Manoel Otávio da Costa; Pires, Marco Túlio Baccarini; Oliveira, Bruna Guimarães; Barros, Vladimir da Costa Val; Barros, Marcio Vinicius Lins; Ribeiro, Antônio Luiz Pinho

    2006-01-01

    The aim of this study was to compare Chagas and non-Chagas' disease patients using single or dual-chamber pacemaker in relation to the ejection fraction of the left ventricle, the ventricular stimulation threshold and the occurrence of ventricular arrhythmia. From January, 2001 to November, 2002, 45 Chagas' disease patients and 35 non-Chagas' disease patients, all pacemaker users, were evaluated considering clinical history, echocardiographic study, Holter monitoring and analysis of the pacemaker telemetry data. Chagas' disease patients were significantly younger, but both groups were similar when chest X-Ray variables and right ventricular stimulation threshold were analyzed. Chagas' disease patients had a lower left ventricular ejection fraction and more frequent ventricular arrhythmia during Holter monitoring. A positive correlation between the low ejection fraction of the left ventricle and the intensity of ventricular arrhythmia was observed. In conclusion, among pacemaker user patients, Chagas' disease is related to cardiac markers of worse prognosis.

  8. Contrast sensitivity through hybrid diffractive, Fresnel, and refractive prisms.

    PubMed

    Katz, Milton

    2004-08-01

    Fresnel and wedge-shaped refractive prisms are used diagnostically and therapeutically in clinical practice. This article extends the study on the effect of prisms on visual acuity to the effect on contrast sensitivity by membrane Fresnel (F), refractive (R), and newly designed hybrid diffractive (C) prisms (ComPrisms), which combine a wedge-shaped refractive prism with a diffractive element. Vistech contrast sensitivity function (CSF) Charts A, B, and C were used to measure the monocular and binocular contrast sensitivity of 21 and 20 subjects, respectively. CSF was measured without prisms (U), through the hybrid diffractive prisms, membrane Fresnel prisms, and acrylic refractive prisms in powers of 20delta, 30delta, and 40delta. Repeated measures analysis of variance calculations resulted in significant main effects in contrast sensitivity across prism types, prism powers, and between monocular and binocular measurements. Results of the Scheffé test for all possible contrast sensitivity comparisons between spatial frequencies are provided. It was found that as prism power increased from 20delta to 40delta, the rate of reduction in area under the CSF curve of ComPrisms became half that of the refractive and Fresnel prisms. Although all three prism types reduced contrast sensitivity with respect to the unaided condition, the ComPrisms at all powers provided significantly better contrast sensitivity than the refractive or Fresnel prisms of equivalent power. Significant binocular summations in contrast sensitivity were found without prisms and across all prism types and powers.

  9. Chagas Disease Risk in Texas

    PubMed Central

    Sarkar, Sahotra; Strutz, Stavana E.; Frank, David M.; Rivaldi, Chissa–Louise; Sissel, Blake; Sánchez–Cordero, Victor

    2010-01-01

    Background Chagas disease, caused by Trypanosoma cruzi, remains a serious public health concern in many areas of Latin America, including México. It is also endemic in Texas with an autochthonous canine cycle, abundant vectors (Triatoma species) in many counties, and established domestic and peridomestic cycles which make competent reservoirs available throughout the state. Yet, Chagas disease is not reportable in Texas, blood donor screening is not mandatory, and the serological profiles of human and canine populations remain unknown. The purpose of this analysis was to provide a formal risk assessment, including risk maps, which recommends the removal of these lacunae. Methods and Findings The spatial relative risk of the establishment of autochthonous Chagas disease cycles in Texas was assessed using a five–stage analysis. 1. Ecological risk for Chagas disease was established at a fine spatial resolution using a maximum entropy algorithm that takes as input occurrence points of vectors and environmental layers. The analysis was restricted to triatomine vector species for which new data were generated through field collection and through collation of post–1960 museum records in both México and the United States with sufficiently low georeferenced error to be admissible given the spatial resolution of the analysis (1 arc–minute). The new data extended the distribution of vector species to 10 new Texas counties. The models predicted that Triatoma gerstaeckeri has a large region of contiguous suitable habitat in the southern United States and México, T. lecticularia has a diffuse suitable habitat distribution along both coasts of the same region, and T. sanguisuga has a disjoint suitable habitat distribution along the coasts of the United States. The ecological risk is highest in south Texas. 2. Incidence–based relative risk was computed at the county level using the Bayesian Besag–York–Mollié model and post–1960 T. cruzi incidence data. This risk

  10. The PRISM/PRIME Project

    NASA Astrophysics Data System (ADS)

    Barlow, R. J.

    2011-09-01

    Lepton Flavour violation is predicted by many theories beyond the standard model. In the muon sector such a violation entails not only direct μ→eγ decay but also the conversion process μ→e. To measure this to high precision requires a large number of muons of very similar energy, and this is difficult to achieve from a muon target with conventional beam optics. PRISM is an FFAG system designed to accept large numbers of muons ( 10/sec) with a wide range of energies, and render them monochromatic by accelerating the less energetic muons and decelerating the more energetic ones. To preserve Liouville's theorem, this is accompanied by a broadening in the timing of the muons, hence the name 'Phase Rotated Intense Slow Muon source.' The principles of this device have been demonstrated and components prototyped. PRIME is a detector (PRISM Muon Electron Conversion) which has been designed to stop 20 MeV bunches of muons in a thin foil, giving a very clean signal and reaching a background sensitivity of 10, four orders of magnitude better than today's limits and probing the interesting region for BSM theories.

  11. Autoimmune Pathogenesis of Chagas Heart Disease

    PubMed Central

    Bonney, Kevin M.; Engman, David M.

    2016-01-01

    Chagas heart disease is an inflammatory cardiomyopathy that develops in approximately one-third of individuals infected with the protozoan parasite Trypanosoma cruzi. Since the discovery of T. cruzi by Carlos Chagas >100 years ago, much has been learned about Chagas disease pathogenesis; however, the outcome of T. cruzi infection is highly variable and difficult to predict. Many mechanisms have been proposed to promote tissue inflammation, but the determinants and the relative importance of each have yet to be fully elucidated. The notion that some factor other than the parasite significantly contributes to the development of myocarditis was hypothesized by the first physician-scientists who noted the conspicuous absence of parasites in the hearts of those who succumbed to Chagas disease. One of these factors—autoimmunity—has been extensively studied for more than half a century. Although questions regarding the functional role of autoimmunity in the pathogenesis of Chagas disease remain unanswered, the development of autoimmune responses during infection clearly occurs in some individuals, and the implications that this autoimmunity may be pathogenic are significant. In this review, we summarize what is known about the pathogenesis of Chagas heart disease and conclude with a view of the future of Chagas disease diagnosis, pathogenesis, therapy, and prevention, emphasizing recent advances in these areas that aid in the management of Chagas disease. PMID:25857229

  12. Abbot Ice Shelf, the Amundsen Sea Continental Margin and the Southern Boundary of the Bellingshausen Plate Seaward of West Antarctica

    NASA Astrophysics Data System (ADS)

    Cochran, J. R.; Tinto, K. J.; Bell, R. E.

    2014-12-01

    The Abbot Ice Shelf extends 450 km along the coast of West Antarctica between 103°W and 89°W and straddles the boundary between the Bellingshausen Sea continental margin, which overlies a former subduction zone, and Amundsen Sea rifted continental margin. Inversion of NASA Operation IceBridge airborne gravity data for sub-ice bathymetry shows that the western part of the ice shelf, as well as Cosgrove Ice Shelf to the south, are underlain by a series of east-west trending rift basins. The eastern boundary of the rifted terrain coincides with the eastern boundary of rifting between Antarctica and Zealandia and the rifts formed during the early stages of this rifting. Extension in these rifts is minor as rifting quickly jumped north of Thurston Island. The southern boundary of the Cosgrove Rift is aligned with the southern boundary of a sedimentary basin under the Amundsen Embayment continental shelf to the west, also formed by Antarctica-Zealandia rifting. The shelf basin has an extension factor, β, of 1.5 - 1.7 with 80 -100 km of extension occurring in an area now ~250 km wide. Following this extension early in the rifting process, rifting centered to the north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf has been tectonically quiescent and has primarily been shaped though subsidence, sedimentation and the passage of the West Antarctic Ice Sheet back and forth across it. The former Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to its incorporation into the Antarctic Plate at ~62 Ma. During the latter part of its existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence between the Bellingshausen and Antarctic plates east of 102°W. Seismic reflection and gravity data show that this convergence is expressed by an area of intensely deformed sediments beneath the continental slope from 102°W to 95°W and

  13. Association of uterine leiomyoma and Chagas' disease.

    PubMed

    Murta, Eddie Fernando Candido; Oliveira, Gustavo Paludetto; Prado, Fernando De Oliveira; De Souza, Maria Azniv Hazarabedian; Tavares Murta, Beatriz Martins; Adad, Sheila Jorge

    2002-03-01

    With the aim of studying the frequency of Chagas' disease among sufferers of uterine leiomyoma, we analyzed women older than 35 years who underwent surgery and presented with leiomyoma on anatomicopathological examination. The diagnosis of Chagas infection was based on positivity to at least two of three serological tests: enzyme-linked immunosorbent assay, passive hemagglutination, and immunofluorescence. The study was case controlled, matching for age, skin color, and parity. The control group consisted of women undergoing surgery for other benign gynecological alterations. During this period, 118 women presented with uterine leiomyoma, 27.1% of whom were serologically positive for Chagas' disease versus 16.1% of the controls (P < 0.05). Matching by skin color and parity showed that 40% of the white multiparous women with uterine leiomyoma had Chagas' disease versus 10% of the controls (P < 0.05). We concluded that there appears to be an association between Chagas' disease and uterine leiomyoma.

  14. The Chronic Gastrointestinal Manifestations of Chagas Disease

    PubMed Central

    Matsuda, Nilce Mitiko; Miller, Steven M.; Evora, Paulo R. Barbosa

    2009-01-01

    Chagas disease is an infectious disease caused by the protozoan Trypanosoma cruzi. The disease mainly affects the nervous system, digestive system and heart. The objective of this review is to revise the literature and summarize the main chronic gastrointestinal manifestations of Chagas disease. The chronic gastrointestinal manifestations of Chagas disease are mainly a result of enteric nervous system impairment caused by T. cruzi infection. The anatomical locations most commonly described to be affected by Chagas disease are salivary glands, esophagus, lower esophageal sphincter, stomach, small intestine, colon, gallbladder and biliary tree. Chagas disease has also been studied in association with Helicobacter pylori infection, interstitial cells of Cajal and the incidence of gastrointestinal cancer. PMID:20037711

  15. PRISM Canada. Priorities in School Mathematics.

    ERIC Educational Resources Information Center

    Alberta Univ., Edmonton. Faculty of Education.

    The Priorities in School Mathematics (PRISM) Canada Project was initiated in September 1977 as a companion study to the National Council of Teachers of Mathematics (NCTM) PRISM Project. These twin projects were designed to help provide guidelines and suggestions for curriculum changes during the 1980's. Two instruments were used, a Preferences…

  16. The Vasculature in Chagas Disease

    PubMed Central

    Prado, Cibele M.; Jelicks, Linda A.; Weiss, Louis M.; Factor, Stephen M.; Tanowitz, Herbert B.; Rossi, Marcos A.

    2013-01-01

    The cardiovascular manifestations of Chagas disease are well known. However, the contribution of the vasculature and specifically the microvasculature has received little attention. This chapter reviews the evidence supporting the notion that alterations in the microvasculature especially in the heart contribute to the pathogenesis of chagasic cardiomyopathy. These data may also be important in understanding the contributions of the microvasculature in the aetiologies of other cardiomyopathies. The role of endothelin-1 and of thromboxane A2 vascular spasm and platelet aggregation is also discussed. Further, these observations may provide target(s) for intervention. PMID:21884888

  17. [Oral transmission of Chagas' disease].

    PubMed

    Toso M, Alberto; Vial U, Felipe; Galanti, Norbel

    2011-02-01

    The traditional transmission pathways of Chagas' disease are vectorial, transfusional, transplacental and organ transplantation. However, oral transmission is gaining importance. The first evidence of oral transmission was reported in Brazil in 1965. Nowadays the oral route is the transmission mode in 50% of cases in the Amazon river zone. Oral infection is produced by the ingestion of infected triatomine bugs or their feces, undercooked meat from infested host animals and food contaminated with urine or anal secretion of infected marsupials. Therefore travelers to those zones should be advised about care to be taken with ingested food. In Chile, this new mode of transmission should be considered in public health policies.

  18. 21 CFR 886.1650 - Ophthalmic bar prism.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic bar prism. 886.1650 Section 886.1650...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1650 Ophthalmic bar prism. (a) Identification. An ophthalmic bar prism is a device that is a bar composed of fused prisms of gradually increasing...

  19. 21 CFR 886.1650 - Ophthalmic bar prism.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic bar prism. 886.1650 Section 886.1650...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1650 Ophthalmic bar prism. (a) Identification. An ophthalmic bar prism is a device that is a bar composed of fused prisms of gradually increasing...

  20. 21 CFR 886.1650 - Ophthalmic bar prism.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic bar prism. 886.1650 Section 886.1650...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1650 Ophthalmic bar prism. (a) Identification. An ophthalmic bar prism is a device that is a bar composed of fused prisms of gradually increasing...

  1. An Easily Constructed Trigonal Prism Model.

    ERIC Educational Resources Information Center

    Yamana, Shukichi

    1984-01-01

    A model of a trigonal prism which is useful for teaching stereochemistry (especially of the neodymium enneahydrate ion), can be made easily by using a sealed, empty envelope. The steps necessary to accomplish this task are presented. (JN)

  2. Evaluation of Deconvolution Methods for PRISM Images

    NASA Astrophysics Data System (ADS)

    Schwind, Peter; Palubinskas, Gintautas; Storch, Tobias; Muller, Rupert

    2008-11-01

    Within the scope of a project by the European Space Agency (ESA), the German Aerospace Center (DLR) is responsible for the establishment of prototype processors for ALOS/AVNIR-2 and ALOS/PRISM data. This processing chain not only includes radiometric and geometric correction for ALOS/AVNIR-2 and ALOS/PRISM but also atmospheric correction for ALOS/AVNIR-2. In addition to that an optional deconvolution step for the ALOS/PRISM data is offered to improve the image quality. This paper gives a short introduction into the processing chain as a whole and a more in-depth look into the deconvolution strategies taken into consideration for ALOS/PRISM images.

  3. An Easily Constructed Trigonal Prism Model.

    ERIC Educational Resources Information Center

    Yamana, Shukichi

    1984-01-01

    A model of a trigonal prism which is useful for teaching stereochemistry (especially of the neodymium enneahydrate ion), can be made easily by using a sealed, empty envelope. The steps necessary to accomplish this task are presented. (JN)

  4. [Validity of the suicidality assessment instrument PRISM-S (Pictoral Representation of Illness Self Measure - Suicidality)].

    PubMed

    Ring, Mariann; Harbauer, Gregor; Haas, Sebastian; Schuetz, Christopher; Andreae, Andreas; Maercker, Andreas; Ajdacic-Gross, Vladeta

    2014-01-01

    In routine clinical practice the assessment of suicidality proves to be difficult and complex. The aim of the present study was to examine if PRISM can be used to measure validly the person's subjectively perceived suicidality. The nonverbal visualization technique PRISM (Pictoral Representation of Illness and Self Measure) has been developed by Büchi et al. (2002) to evaluate the perceived burden of suffering due to physical illness. The adapted version of PRISM used in our study is called PRISM-S (Pictoral Representation of Illness and Self Measure - Suicidality). 156 eligible inpatients, admitted voluntarily to the crisis intervention centre Winterthur, participated in the study. We used as gold standards the well established assessment tools the Beck Scale of Suicide Ideation (BSS) and the Depressive Symptome Inventory - Subscale (DSI-SS). The results showed high correlations between PRISM-S and the BSS (r = - 0,73) and the DSI-SS scores (r = - 0,76). Clinicians, general practitioners, psychiatrists and psychologists receive with PRISM-S a valid suicidality assessment tool that is very brief and easy to administer in clinical settings.

  5. Chagas Heart Disease: Report on Recent Developments

    PubMed Central

    Machado, Fabiana S.; Jelicks, Linda A.; Kirchhoff, Louis V.; Shirani, Jamshid; Nagajyothi, Fnu; Mukherjee, Shankar; Nelson, Randin; Coyle, Christina M.; Spray, David C.; Campos de Carvalho, Antonio C.; Guan, Fangxia; Prado, Cibele M.; Lisanti, Michael P.; Weiss, Louis M.; Montgomery, Susan P.; Tanowitz, Herbert B.

    2011-01-01

    Chagas disease, caused by the parasite Trypanosoma cruzi, is an important cause of cardiac disease in endemic areas of Latin America. It is now being diagnosed in non-endemic areas due to immigration. Typical cardiac manifestations of Chagas disease include dilated cardiomyopathy, congestive heart failure, arrhythmias, cardioembolism and stroke. Clinical and laboratory-based research to define the pathology resulting from T. cruzi infection has shed light on many of the cellular and molecular mechanisms leading to these manifestations. Antiparasitic treatment may not be appropriate for patients with advanced cardiac disease. Clinical management of Chagas heart disease is similar to that used for cardiomyopathies due to other processes. Cardiac transplantation has been successfully performed in a small number of patients with Chagas heart disease. PMID:22293860

  6. Chagas' disease as a foodborne illness.

    PubMed

    Pereira, Karen Signori; Schmidt, Flávio Luis; Guaraldo, Ana M A; Franco, Regina M B; Dias, Viviane L; Passos, Luiz A C

    2009-02-01

    Various researchers have studied the importance of the oral transmission of Chagas' disease since the mid-20th century. Only in recent years, due to an outbreak that occurred in the Brazilian State of Santa Catarina in 2005 and to various outbreaks occurring during the last 3 years in the Brazilian Amazon basin, mainly associated with the consumption of Amazonian palm berry or açaí (Euterpe oleracea Mart.) juice, has this transmission route aroused the attention of researchers. Nevertheless, reports published in the 1960s already indicated the possibility of Chagas' disease transmission via food in Brazil, mainly in the Amazonian region. Recently, in December 2007, an outbreak of Chagas' disease occurred in Caracas, Venezuela, related to ingestion of contaminated fruit juices. The objective of this article is to point out the importance of foodborne transmission in the etiology of Chagas' disease, on the basis of published research and Brazilian epidemiology data.

  7. Chaga mushroom-induced oxalate nephropathy.

    PubMed

    Kikuchi, Yuko; Seta, Koichi; Ogawa, Yayoi; Takayama, Tatsuya; Nagata, Masao; Taguchi, Takashi; Yahata, Kensei

    2014-06-01

    Chaga mushrooms have been used in folk and botanical medicine as a remedy for cancer, gastritis, ulcers, and tuberculosis of the bones. A 72-year-old Japanese female had been diagnosed with liver cancer 1 year prior to presenting at our department. She underwent hepatectomy of the left lobe 3 months later. Chaga mushroom powder (4 - 5 teaspoons per day) had been ingested for the past 6 months for liver cancer. Renal function decreased and hemodialysis was initiated. Renal biopsy specimens showed diffuse tubular atrophy and interstitial fibrosis. Oxalate crystals were detected in the tubular lumina and urinary sediment and oxalate nephropathy was diagnosed. Chaga mushrooms contain extremely high oxalate concentrations. This is the first report of a case of oxalate nephropathy associated with ingestion of Chaga mushrooms.

  8. Resolution of a Prism Waveguide Spectrum Analyzer

    NASA Astrophysics Data System (ADS)

    Shul‧ga, A. V.

    2013-11-01

    We have studied the resolution of a waveguide spectrum analyzer, based on a prism coupler for mode excitation, as a function of the structural parameters of the waveguide. We show that the limiting resolution of the waveguide spectrum analyzer is determined by the ratio of the chromatic dispersion of the waveguide to the imaginary part of the propagation constant for the leaky mode of the waveguide/coupling prism structure.

  9. OPERA: Objective Prism Enhanced Reduction Algorithms

    NASA Astrophysics Data System (ADS)

    Universidad Complutense de Madrid Astrophysics Research Group

    2015-09-01

    OPERA (Objective Prism Enhanced Reduction Algorithms) automatically analyzes astronomical images using the objective-prism (OP) technique to register thousands of low resolution spectra in large areas. It detects objects in an image, extracts one-dimensional spectra, and identifies the emission line feature. The main advantages of this method are: 1) to avoid subjectivity inherent to visual inspection used in past studies; and 2) the ability to obtain physical parameters without follow-up spectroscopy.

  10. Ray picture for prism-film coupling

    NASA Astrophysics Data System (ADS)

    Hoekstra, H. J. W. M.; van't Spijker, J. C.; Koerkamp, H. M. M. Klein

    1993-10-01

    Tien and Ulrich introduced a description of the prism-film coupler, with use of the ray picture. The model given is discussed, and it is argued that the effect of the Goss-Hanchen shift cannot be neglected in general. Relatively simple expressions are given for the computation of the coupling efficiency of a prism-loaded planar structure as a function of the angle of incidence of the incoming beam. Computational results are presented and compared with those of other methods.

  11. Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica

    NASA Astrophysics Data System (ADS)

    Cochran, James R.; Tinto, Kirsty J.; Bell, Robin E.

    2015-05-01

    Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β, of 1.5-1.7 with 80-100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts. The copyright line for this article was changed on 5 JUN 2015 after original online publication.

  12. Liquid Temperature Measurements Using Two Different Tunable Hollow Prisms

    PubMed Central

    Calixto, Sergio; Rosete-Aguilar, Martha; Torres-Gomez, Ismael

    2017-01-01

    This paper describes the design, fabrication, and testing of two hollow prisms. One is a prism with a grating glued to its hypotenuse. This ensemble, prism + grating, is called a grism. It can be applied as an on-axis tunable spectrometer. The other hollow prism is a constant deviation one called a Pellin-Broca. It can be used as a tunable dispersive element in a spectrometer with no moving parts. The application of prisms as temperature sensors is shown. PMID:28146068

  13. Liquid Temperature Measurements Using Two Different Tunable Hollow Prisms.

    PubMed

    Calixto, Sergio; Rosete-Aguilar, Martha; Torres-Gomez, Ismael

    2017-01-29

    This paper describes the design, fabrication, and testing of two hollow prisms. One is a prism with a grating glued to its hypotenuse. This ensemble, prism + grating, is called a grism. It can be applied as an on-axis tunable spectrometer. The other hollow prism is a constant deviation one called a Pellin-Broca. It can be used as a tunable dispersive element in a spectrometer with no moving parts. The application of prisms as temperature sensors is shown.

  14. Neutron energy analysis by silicon prisms

    NASA Astrophysics Data System (ADS)

    Schulz, J.; Ott, F.; Hülsen, Ch.; Krist, Th.

    2013-11-01

    Neutron energy analysing by refraction with prisms allows to measure different wavelengths at the same time thus avoiding losses due to monochromatization. We built and tested a refractive energy analysing device made from small prisms, where losses only occur due to the attenuation in the material. We measured the refraction and the transmission of MgF2 and Si prisms at the V14 reflectometer in Berlin at 4.9 Å to check their applicability. The experimentally determined linear attenuation coefficients are 0.055 cm-1 for the MgF2 and 0.03 cm-1 for the Si prisms. An energy analyser consisting of silicon prism layers was measured at the EROS reflectometer at the LLB in a white neutron beam. The useful wavelength band was 2.4-7.6 Å. At 6.7 Å a wavelength resolution of 5% and a transmission of 53% were achieved. The surface roughness of the prisms could be determined to be (0.011±0.006)deg.

  15. Chagas Disease Cardiomyopathy: Immunopathology and Genetics

    PubMed Central

    Chevillard, Christophe

    2014-01-01

    Chagas disease, caused by the protozoan Trypanosoma cruzi, is endemic in Latin America and affects ca. 10 million people worldwide. About 30% of Chagas disease patients develop chronic Chagas disease cardiomyopathy (CCC), a particularly lethal inflammatory cardiomyopathy that occurs decades after the initial infection, while most patients remain asymptomatic. Mortality rate is higher than that of noninflammatory cardiomyopathy. CCC heart lesions present a Th1 T-cell-rich myocarditis, with cardiomyocyte hypertrophy and prominent fibrosis. Data suggest that the myocarditis plays a major pathogenetic role in disease progression. Major unmet goals include the thorough understanding of disease pathogenesis and therapeutic targets and identification of prognostic genetic factors. Chagas disease thus remains a neglected disease, with no vaccines or antiparasitic drugs proven efficient in chronically infected adults, when most patients are diagnosed. Both familial aggregation of CCC cases and the fact that only 30% of infected patients develop CCC suggest there might be a genetic component to disease susceptibility. Moreover, previous case-control studies have identified some genes associated to human susceptibility to CCC. In this paper, we will review the immunopathogenesis and genetics of Chagas disease, highlighting studies that shed light on the differential progression of Chagas disease patients to CCC. PMID:25210230

  16. Orally-transmitted Chagas disease.

    PubMed

    Filigheddu, Maria Teresa; Górgolas, Miguel; Ramos, José Manuel

    2017-02-09

    Chagas disease is a zoonosis caused by protozoan parasite Trypanosoma cruzi, which is most frequently associated with a vectorial transmission. However, in recent years we have observed a significant increase in the oral transmission of the disease, associated mainly with the consumption of drinks made from fruit or other vegetables contaminated with triatomine faeces or secretions from infected mammals. After a latency period of 3 to 22 days after ingestion, the oral infection is characterized by more severe manifestations than those associated with vectorial transmission: prolonged fever, acute myocarditis with heart failure and, in some cases, meningoencephalitis. Mortality can reach up to 33% of those infected. The aim of this paper is to review this matter and to promote prevention practices. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  17. Lymphocyte Transformation in Chagas Disease

    PubMed Central

    Tschudi, E. Irene; Anziano, Dante F.; Dalmasso, Agustin P.

    1972-01-01

    The in vitro response of human peripheral lymphocytes to Trypanosoma (Schizotrypanum) cruzi antigens and to phytohemagglutinin was used to study the role of cellular immunity in Chagas disease (American trypanosomiasis). Solubilized T. cruzi antigens elicited 5 to 30% transformed cells in 5-day cultures of lymphocytes from adults chronically infected with T. cruzi. No major difference was noted between the response of 22 asymptomatic individuals and of 3 patients with chagasic cardiopathy. No correlation was found between degree of lymphocytic transformation and serum antibody titer. Lymphocytes from 15 normal controls yielded no significant transformation. Intradermal tests provoked a local delayed hypersensitivity reaction in infected individuals only, as evaluated clinically and histologically. The response to phytohemagglutinin of lymphocytes from chronically infected individuals was identical with that of normal controls. Images PMID:4629392

  18. Carlos Chagas Discoveries as a Drop Back to Scientific Construction of Chronic Chagas Heart Disease

    PubMed Central

    Bestetti, Reinaldo B.; Restini, Carolina Baraldi A.; Couto, Lucélio B.

    2016-01-01

    The scientific construction of chronic Chagas heart disease (CCHD) started in 1910 when Carlos Chagas highlighted the presence of cardiac arrhythmia during physical examination of patients with chronic Chagas disease, and described a case of heart failure associated with myocardial inflammation and nests of parasites at autopsy. He described sudden cardiac death associated with arrhythmias in 1911, and its association with complete AV block detected by Jacquet's polygraph as Chagas reported in 1912. Chagas showed the presence of myocardial fibrosis underlying the clinical picture of CCHD in 1916, he presented a full characterization of the clinical aspects of CCHD in 1922. In 1928, Chagas detected fibrosis of the conductive system, and pointed out the presence of marked cardiomegaly at the chest X-Ray associated with minimal symptomatology. The use of serological reaction to diagnose CCHD was put into clinical practice in 1936, after Chagas' death, which along with the 12-lead ECG, revealed the epidemiological importance of CCHD in 1945. In 1953, the long period between initial infection and appearance of CCHD was established, whereas the annual incidence of CCHD from patients with the indeterminate form of the disease was established in 1956. The use of heart catheterization in 1965, exercise stress testing in 1973, Holter monitoring in 1975, Electrophysiologic testing in 1973, echocardiography in 1975, endomyocardial biopsy in 1981, and Magnetic Resonance Imaging in 1995, added to the fundamental clinical aspects of CCHD as described by Carlos Chagas. PMID:27223644

  19. Carlos Chagas Discoveries as a Drop Back to Scientific Construction of Chronic Chagas Heart Disease.

    PubMed

    Bestetti, Reinaldo B; Restini, Carolina Baraldi A; Couto, Lucélio B

    2016-07-01

    The scientific construction of chronic Chagas heart disease (CCHD) started in 1910 when Carlos Chagas highlighted the presence of cardiac arrhythmia during physical examination of patients with chronic Chagas disease, and described a case of heart failure associated with myocardial inflammation and nests of parasites at autopsy. He described sudden cardiac death associated with arrhythmias in 1911, and its association with complete AV block detected by Jacquet's polygraph as Chagas reported in 1912. Chagas showed the presence of myocardial fibrosis underlying the clinical picture of CCHD in 1916, he presented a full characterization of the clinical aspects of CCHD in 1922. In 1928, Chagas detected fibrosis of the conductive system, and pointed out the presence of marked cardiomegaly at the chest X-Ray associated with minimal symptomatology. The use of serological reaction to diagnose CCHD was put into clinical practice in 1936, after Chagas' death, which along with the 12-lead ECG, revealed the epidemiological importance of CCHD in 1945. In 1953, the long period between initial infection and appearance of CCHD was established, whereas the annual incidence of CCHD from patients with the indeterminate form of the disease was established in 1956. The use of heart catheterization in 1965, exercise stress testing in 1973, Holter monitoring in 1975, Electrophysiologic testing in 1973, echocardiography in 1975, endomyocardial biopsy in 1981, and Magnetic Resonance Imaging in 1995, added to the fundamental clinical aspects of CCHD as described by Carlos Chagas.

  20. American Trypanosomiasis (Also Known as Chagas Disease) Diagnosis

    MedlinePlus

    ... The CDC Parasites - American Trypanosomiasis (also known as Chagas Disease) Note: Javascript is disabled or is not ... message, please visit this page: About CDC.gov . Chagas Disease General Information Detailed FAQs Blood Screening FAQs ...

  1. American Trypanosomiasis (Also Known as Chagas Disease) Blood Screening FAQs

    MedlinePlus

    ... Tropical Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Blood Screening FAQs Language: English Español (Spanish) Recommend on ... be concerned about getting Chagas disease? Why are blood banks now screening for Chagas disease? The transmission ...

  2. The PRISM3D paleoenvironmental reconstruction

    USGS Publications Warehouse

    Dowsett, H.; Robinson, M.; Haywood, A.M.; Salzmann, U.; Hill, Daniel; Sohl, L.E.; Chandler, M.; Williams, Mark; Foley, K.; Stoll, D.K.

    2010-01-01

    The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) paleoenvironmental reconstruction is an internally consistent and comprehensive global synthesis of a past interval of relatively warm and stable climate. It is regularly used in model studies that aim to better understand Pliocene climate, to improve model performance in future climate scenarios, and to distinguish model-dependent climate effects. The PRISM reconstruction is constantly evolving in order to incorporate additional geographic sites and environmental parameters, and is continuously refined by independent research findings. The new PRISM three dimensional (3D) reconstruction differs from previous PRISM reconstructions in that it includes a subsurface ocean temperature reconstruction, integrates geochemical sea surface temperature proxies to supplement the faunal-based temperature estimates, and uses numerical models for the first time to augment fossil data. Here we describe the components of PRISM3D and describe new findings specific to the new reconstruction. Highlights of the new PRISM3D reconstruction include removal of Hudson Bay and the Great Lakes and creation of open waterways in locations where the current bedrock elevation is less than 25m above modern sea level, due to the removal of the West Antarctic Ice Sheet and the reduction of the East Antarctic Ice Sheet. The mid-Piacenzian oceans were characterized by a reduced east-west temperature gradient in the equatorial Pacific, but PRISM3D data do not imply permanent El Niño conditions. The reduced equator-to-pole temperature gradient that characterized previous PRISM reconstructions is supported by significant displacement of vegetation belts toward the poles, is extended into the Arctic Ocean, and is confirmed by multiple proxies in PRISM3D. Arctic warmth coupled with increased dryness suggests the formation of warm and salty paleo North Atlantic Deep Water (NADW) and a more vigorous thermohaline circulation system that may

  3. How to Get the Full Prism Effect

    PubMed Central

    Fahle, Manfred

    2015-01-01

    We investigate how the immediate correction effect decreases mispointing under prisms. Subjects performed rhythmic pointing movements under different conditions with horizontally shifting prisms. Even the first (initial) pointing error is much smaller than the prismatic shift, a phenomenon called the immediate correction effect. Knowledge about the structure of the room and of objects in the room obtained before the prisms were worn may limit the amount of the prismatic displacement perceived. We therefore compared the direct prism effect as well as prismatic adaptation with room illumination switched on versus switched off. Our 44 subjects participated in two experiments, with varying amounts of information about room structure available. The results show a direct effect corresponding to the optical power of the prisms in the dark condition, when in addition body position was slightly rotated in direction of the prismatic shift. But even in the dark, a significant immediate correction effect arises with the fixed body position. The largest immediate correction amounting to almost half of optical displacement arose in the standard condition of bright light and fixed body position. PMID:27433319

  4. [Chagas disease with the acquired immunodeficiency syndrome. Clinical cases].

    PubMed

    Labarca, J; Acuña, G; Saavedra, H; Oddó, D; Sepúlveda, C; Ballesteros, J; Alvarez, M

    1992-02-01

    We report 2 patients with AIDS who developed Chagas infection, one with encephalitis, the other with acute myocarditis. The implications of immune depression for the manifestations and course of Chagas disease are discussed. Chagas disease should be considered in patients with AIDS who live in endemic zones and who develop cerebral or cardiac manifestations.

  5. Infrared camera PICNIC and prism-spectropolarimeter

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yukiyasu; Fang, Geng; Minezaki, Takeo; Waseda, Kohichi; Nakamura, Kyoko; Sato, Shuji

    1994-06-01

    We constructed a near IR camera PICNIC equipped with the 2D array detector NICMOS-3 manufactured by Rockwell. Employing a four aspherical metal mirror system for reimaging optics, PICNIC is an IR imager distinguished with high throughput and small chromatic aberration. In addition to normal imaging mode, the camera has a prism spectroscopy mode and a polarimetry mode. A direct view prism, which can be optionally inserted in front of the camera, make it possible to obtain multiobject low resolution spectroscopy in the wavelength range from 1 to 2.5 micrometers at resolving power of approximately 50. Linear polarization can be measured with combination of the filters and/or the prism. We realized user-friendly operating environment as well as automated observation.

  6. Dispersion compensation based on prism compressor

    NASA Astrophysics Data System (ADS)

    Liu, Hongying; Lan, Tian; Chen, Xiaomei; Ni, Guoqiang

    2017-04-01

    A prism compressor can compensate dispersion of femtosecond light pulses travelling in air for laser ranging. An accurate expression of the group delay dispersion (GDD) of a prism compressor at arbitrary incident angle and at arbitrary incident point is obtained, which is of benefit to finely compensating dispersion of femtosecond pulses. Influences of several parameters on group delay dispersion are analyzed for the active compensation of dispersion of femtosecond pulses. These expressions are convenient to applications of intra- and extra-cavity dispersion compensation of ultra-short laser pulses, as well as fine compensation of satellite laser ranging and laser altimetry.

  7. Chagas Disease and Breast-feeding

    PubMed Central

    López-Vélez, Rogelio

    2013-01-01

    Chagas disease (infection by the protozoan Trypanosoma cruzi) is a major parasitic disease of the Americas and one of the main neglected tropical diseases. Although various routes of transmission sre recognized, the risk for transmission of the infection through breast-feeding has not clearly been established. We reviewed the literature on transmission of T. cruzi through breast-feeding to provide breast-feeding mothers with Chagas disease with medical guidance. Although data from animal studies and human studies are scarce, we do not recommend that mothers with Chagas disease discontinue breast-feeding, unless they are experiencing the acute phase of the disease, reactivated disease resulting from immunosuppression, or bleeding nipples. In these cases, thermal treatment of milk before feeding the infant may be considered. PMID:24050257

  8. [Part VI. Antiparasitic treatment for Chagas disease].

    PubMed

    B, Werner Apt; G, Ingrid Heitmann; L, M Isabel Jercic; M, Leonor Jofré; V, Patricia Muñoz C Del; H, Isabel Noemí; V, Ana M San Martín; P, Jorge Sapunar; H, Marisa Torres; A, Inés Zulantay

    2008-10-01

    As expert consensus has been arisen about universal antiparasitic treatment for all patients infected with Trypanosoma cruzi, most important drugs licensed for Chagas disease treatment are reviewed: nifurtimox and benznidazol, their mechanisms of action, doses, treatment schedules, adverse effects and contraindications. Two other drugs used for Chagas disease treatment, for which a Chilean experience may be exhibited, are allopurinol and itraconazole. Indications for treatment of Chagas disease in immunocompetent patients and immunocompromised hosts are detailed. This chapter refers besides to the evaluation and monitoring of antiparasitic therapy in immunocompromised patients, the availability of drugs and includes various forms facsimiles suggested to perform clinical and laboratory follow up of patients that undergo treatment, indicating the prescribed drug, adverse effects and time of follow up.

  9. Chagas disease and breast-feeding.

    PubMed

    Norman, Francesca F; López-Vélez, Rogelio

    2013-10-01

    Chagas disease (infection by the protozoan Trypanosoma cruzi) is a major parasitic disease of the Americas and one of the main neglected tropical diseases. Although various routes of transmission sre recognized, the risk for transmission of the infection through breast-feeding has not clearly been established. We reviewed the literature on transmission of T. cruzi through breast-feeding to provide breast-feeding mothers with Chagas disease with medical guidance. Although data from animal studies and human studies are scarce, we do not recommend that mothers with Chagas disease discontinue breast-feeding, unless they are experiencing the acute phase of the disease, reactivated disease resulting from immunosuppression, or bleeding nipples. In these cases, thermal treatment of milk before feeding the infant may be considered.

  10. Developments in the management of Chagas cardiomyopathy.

    PubMed

    Tanowitz, Herbert B; Machado, Fabiana S; Spray, David C; Friedman, Joel M; Weiss, Oren S; Lora, Jose N; Nagajyothi, Jyothi; Moraes, Diego N; Garg, Nisha Jain; Nunes, Maria Carmo P; Ribeiro, Antonio Luiz P

    2015-12-01

    Over 100 years have elapsed since the discovery of Chagas disease and there is still much to learn regarding pathogenesis and treatment. Although there are antiparasitic drugs available, such as benznidazole and nifurtimox, they are not totally reliable and often toxic. A recently released negative clinical trial with benznidazole in patients with chronic Chagas cardiomyopathy further reinforces the concerns regarding its effectiveness. New drugs and new delivery systems, including those based on nanotechnology, are being sought. Although vaccine development is still in its infancy, the reality of a therapeutic vaccine remains a challenge. New ECG methods may help to recognize patients prone to developing malignant ventricular arrhythmias. The management of heart failure, stroke and arrhythmias also remains a challenge. Although animal experiments have suggested that stem cell based therapy may be therapeutic in the management of heart failure in Chagas cardiomyopathy, clinical trials have not been promising.

  11. Developments in the management of Chagas cardiomyopathy

    PubMed Central

    Tanowitz, Herbert B; Machado, Fabiana S; Spray, David C; Friedman, Joel M; Weiss, Oren S; Lora, Jose N; Nagajyothi, Jyothi; Moraes, Diego N; Garg, Nisha Jain; Nunes, Maria Carmo P; Ribeiro, Antonio Luiz P

    2016-01-01

    Over 100 years have elapsed since the discovery of Chagas disease and there is still much to learn regarding pathogenesis and treatment. Although there are antiparasitic drugs available, such as benznidazole and nifurtimox, they are not totally reliable and often toxic. A recently released negative clinical trial with benznidazole in patients with chronic Chagas cardiomyopathy further reinforces the concerns regarding its effectiveness. New drugs and new delivery systems, including those based on nanotechnology, are being sought. Although vaccine development is still in its infancy, the reality of a therapeutic vaccine remains a challenge. New ECG methods may help to recognize patients prone to developing malignant ventricular arrhythmias. The management of heart failure, stroke and arrhythmias also remains a challenge. Although animal experiments have suggested that stem cell based therapy may be therapeutic in the management of heart failure in Chagas cardiomyopathy, clinical trials have not been promising. PMID:26496376

  12. Posterior parietal cortex and the dissociable components of prism adaptation.

    PubMed

    Newport, R; Jackson, S R

    2006-01-01

    Recent evidence has implicated posterior parietal cortex (PPC) in adaptation to optical displacing prisms. It has been suggested that PPC contributes to the strategic component of prism adaptation necessary for perceptual realignment (true adaptation). It has also been suggested, however, that the part of PPC responsible for corrections to ongoing movements (a putative strategic component) may not be necessary for successful adaptation. A patient presenting with bilateral posterior parietal damage (patient JJ) was tested with both hands on two versions of a prism adaptation task--one using prism goggles and one using a virtual prism arrangement. JJ displayed independent deficits: his right hand failed to show strategic control, yet adapted fully to the prisms whereas his left hand showed evidence of strategic control without subsequent adaptation. The data indicates that the ability to implement control strategies may not be necessary for successful adaptation to prisms. A proposed model for the role of posterior parietal cortex in prism adaptation is also presented.

  13. [Research on improving spectrum resolution of optimized Wollaston prism array].

    PubMed

    Zhang, Peng; Wang, Jian-Rong; Zhang, Guo-Chen; Hou, Wen

    2011-11-01

    In order to not affect the image quality of interference fringes on the basis of the structure by increasing the structure angle of Wollaston prism to improve spectrum resolution, the authors optimized the structure of Wollaston prism. Calculating the function of the splitting angle and the structure angle, analysis indicated that taking the isosceles triangle prism with the same nature of the second wedge-shaped prism after the Wollaston prism, which makes the o and e light parallel to the optical axis, and alpha=0 degrees, the imaging interference fringes are no longer affected by changes in the splitting angle. Several optimized Wollaston prisms were made as an array to improve the spectral resolution. Experiments used traditional and optimized Wollaston prism array to detect the spectrum of the 980 nm laser. Experimental data showed that using optimized Wollaston prism array gets a clearer contrast of interference fringes, and the spectral data with Fourier transform are more accurate with DSP.

  14. Ultradispersive adaptive prism based on a coherently prepared atomic medium

    SciTech Connect

    Sautenkov, Vladimir A.; Li Hebin; Rostovtsev, Yuri V.; Scully, Marlan O.

    2010-06-15

    We have experimentally demonstrated an ultra-dispersive optical prism made from a coherently driven Rb atomic vapor. The prism possesses spectral angular dispersion that is 6 orders of magnitude higher than that of a prism made of optical glass; such angular dispersion allows one to spatially resolve light beams with different frequencies separated by a few kilohertz. The prism operates near the resonant frequency of atomic vapor and its dispersion is optically controlled by a coherent driving field.

  15. High-Power Prismatic Devices for Oblique Peripheral Prisms.

    PubMed

    Peli, Eli; Bowers, Alex R; Keeney, Karen; Jung, Jae-Hyun

    2016-05-01

    Horizontal peripheral prisms for hemianopia provide field expansion above and below the horizontal meridian; however, there is a vertical gap leaving the central area (important for driving) without expansion. In the oblique design, tilting the bases of both prism segments toward the horizontal meridian moves the field expansion area vertically and centrally (closing the central gap) while the prisms remain in the peripheral location. However, tilting the prisms results also in a reduction of the lateral field expansion. Higher prism powers are needed to counter this effect. We developed, implemented, and tested a series of designs aimed at increasing the prism power to reduce the central gap while maintaining wide lateral expansion. The designs included inserting the peripheral prisms into carrier lenses that included yoked prism in the opposite direction, combination of two Fresnel segments attached at the base and angled to each other (bi-part prisms), and creating Fresnel prism-like segments from nonparallel periscopic mirror pairs (reflective prisms). A modest increase in lateral power was achieved with yoked-prism carriers. Bi-part combination of 36Δ Fresnel segments provided high power with some reduction in image quality. Fresnel reflective prism segments have potential for high power with superior optical quality but may be limited in field extent or by interruptions of the expanded field. Extended apical scotomas, even with unilateral fitting, may limit the utility of very high power prisms. The high-power bi-part and reflective prisms enable a wider effective eye scanning range (more than 15 degrees) into the blind hemifield. Conventional prisms of powers higher than the available 57Δ are limited by the binocular impact of a wider apical scotoma and a reduced effective eye scanning range to the blind side. The various designs that we developed may overcome these limitations and find use in various other field expansion applications.

  16. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine position...

  17. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings which...

  18. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings which...

  19. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld and...

  20. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine position...

  1. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld and...

  2. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine position...

  3. Symmetry Breaking Analysis of Prism Adaptation's Latent Aftereffect

    ERIC Educational Resources Information Center

    Frank, Till D.; Blau, Julia J. C.; Turvey, Michael T.

    2012-01-01

    The effect of prism adaptation on movement is typically reduced when the movement at test (prisms off) differs on some dimension from the movement at training (prisms on). Some adaptation is latent, however, and only revealed through further testing in which the movement at training is fully reinstated. Applying a nonlinear attractor dynamic model…

  4. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine position...

  5. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld and...

  6. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine position...

  7. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld and...

  8. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings which...

  9. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings which...

  10. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings which...

  11. The Program for Regional and International Shorebird Monitoring (PRISM)

    Treesearch

    Jonathan Bart; Brad Andres; Stephen Brown; Garry Donaldson; Brian Harrington; Vicky Johnston; Stephanie Jones; Guy Morrison; Susan Skagen

    2005-01-01

    This report describes the “Program for Regional and International Shorebird Monitoring” (PRISM). PRISM is being implemented by a Canada-United States Shorebird Monitoring and Assessment Committee formed in 2001 by the Canadian Shorebird Working Group and the U.S. Shorebird Council. PRISM provides a single blueprint for implementing the shorebird...

  12. Symmetry Breaking Analysis of Prism Adaptation's Latent Aftereffect

    ERIC Educational Resources Information Center

    Frank, Till D.; Blau, Julia J. C.; Turvey, Michael T.

    2012-01-01

    The effect of prism adaptation on movement is typically reduced when the movement at test (prisms off) differs on some dimension from the movement at training (prisms on). Some adaptation is latent, however, and only revealed through further testing in which the movement at training is fully reinstated. Applying a nonlinear attractor dynamic model…

  13. Comparing the Volumes of Rectangular Prisms

    ERIC Educational Resources Information Center

    Assuah, Charles K.; Wiest, Lynda R.

    2010-01-01

    Can middle-grades students determine which of two rectangular prisms has a larger volume? Can they do so without using a formula? Geometry, and particularly the concept of volume, is important in many subjects, such as physics and chemistry. Students greatly enhance their mathematics knowledge when they make generalizations and construct arguments…

  14. Dual-prism interferometer for collimation testing

    SciTech Connect

    Hii, King Ung; Kwek, Kuan Hiang

    2009-01-10

    An air-wedge lateral-shear interferometer using two prisms is presented. With a variable shear, the interferometer is suitable for testing collimation of a wide range of beam sizes down to a few millimeters in diameter. No antireflection coatings are necessary. Collimation for a light source with short coherent length is also demonstrated.

  15. Reflecting Schmidt/Littrow Prism Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Page, N. A.; Shack, R. V.; Shannon, R. R.

    1985-01-01

    High resolution achieved with wide field of view. Imaging Spectrometer features off-axis reflecting optics, including reflecting "slit" that also serves as field flattener. Only refracting element is prism. By scanning slit across object or scene and timing out signal, both spectral and spatial information in scene are obtained.

  16. Prisms Throw Light on Developmental Disorders

    ERIC Educational Resources Information Center

    Brookes, Rebecca L.; Nicolson, Roderick I.; Fawcett, Angela J.

    2007-01-01

    Prism adaptation, in which the participant adapts to prismatic glasses that deflect vision laterally, is a specific test of cerebellar function. Fourteen dyslexic children (mean age 13.5 years); 14 children with developmental coordination disorder (DCD): 6 of whom had comorbid dyslexia; and 12 control children matched for age and IQ underwent…

  17. Behavioral Consultant Application. PRISM Project Technical Report.

    ERIC Educational Resources Information Center

    Smith, Jesse

    This brief paper describes the Peer Coaching Rural In-Service Model (PRISM) Behavioral Consultant (PBC) program, an online tool for teachers that provides advice on handling simple classroom behavior problems. PBC's advice is based on a series of rules and expressions used by the computer program to make inferences and eliminate inappropriate…

  18. PRISM3 Pliocene Sea surface Temperature Reconstruction

    NASA Astrophysics Data System (ADS)

    Dowsett, H.; Robinson, M.; Foley, K.; Caballero, R.

    2008-12-01

    The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project provides a conceptual model and synoptic view of the earth during a considerably warmer than modern (2-3°C warmer global mean annual temperature) interval (mid-Piacenzian Age, Pliocene Epoch; ~3.3 to 3.0 Ma) through reconstruction of sea-surface temperature (SST) and other paleoenvironmental parameters. The PRISM3 SST fields include new equatorial Pacific and subpolar - polar North Atlantic components based upon multiproxy (faunal, alkenone and Mg/Ca) temperature analyses from new sites. These data are presented in 12 interpolated global fields with 2° spatial resolution representing monthly SST estimates. Results show a reduced longitudinal temperature gradient across the equatorial Pacific and extension of warm North Atlantic surface conditions into the eastern regions of the Arctic Ocean near Spitzbergen. These data are part of the PRISM3 paleoenvironmental reconstruction designed in part to provide climate modeling groups with new SST and alternative land cover reconstructions, 3-dimensional deep ocean temperature, topography and sea level. The PRISM3 reconstruction is the primary data source for the new Pliocene Climate Model Intercomparison Project (PlioMIP).

  19. Precise Global DEM Generation by ALOS PRISM

    NASA Astrophysics Data System (ADS)

    Tadono, T.; Ishida, H.; Oda, F.; Naito, S.; Minakawa, K.; Iwamoto, H.

    2014-04-01

    The Japan Aerospace Exploration Agency (JAXA) generated the global digital elevation/surface model (DEM/DSM) and orthorectified image (ORI) using the archived data of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS, nicknamed "Daichi"), which was operated from 2006 to 2011. PRISM consisted of three panchromatic radiometers that acquired along-track stereo images. It had a spatial resolution of 2.5 m in the nadir-looking radiometer and achieved global coverage, making it a suitable potential candidate for precise global DSM and ORI generation. In the past 10 years or so, JAXA has conducted the calibration of the system corrected standard products of PRISM in order to improve absolute accuracies as well as to validate the high-level products such as DSM and ORI. In this paper, we introduce an overview of the global DEM/DSM dataset generation project, including a summary of ALOS and PRISM, in addition to the global data archive status. It is also necessary to consider data processing strategies, since the processing capabilities of the level 1 standard product and the high-level products must be developed in terms of both hardware and software to achieve the project aims. The automatic DSM/ORI processing software and its test processing results are also described.

  20. Comparing Volumes of Prisms and Pyramids

    ERIC Educational Resources Information Center

    Vinogradova, Natalya

    2012-01-01

    Students' experience in using formulas for volumes is often limited to substituting numbers into given formulas. An activity presented in this article may help students make connections between the formulas for volumes of prisms and volumes of pyramids. In addition, some interesting facts from number theory arise, demonstrating strong connections…

  1. Comparing Volumes of Prisms and Pyramids

    ERIC Educational Resources Information Center

    Vinogradova, Natalya

    2012-01-01

    Students' experience in using formulas for volumes is often limited to substituting numbers into given formulas. An activity presented in this article may help students make connections between the formulas for volumes of prisms and volumes of pyramids. In addition, some interesting facts from number theory arise, demonstrating strong connections…

  2. Prisms Throw Light on Developmental Disorders

    ERIC Educational Resources Information Center

    Brookes, Rebecca L.; Nicolson, Roderick I.; Fawcett, Angela J.

    2007-01-01

    Prism adaptation, in which the participant adapts to prismatic glasses that deflect vision laterally, is a specific test of cerebellar function. Fourteen dyslexic children (mean age 13.5 years); 14 children with developmental coordination disorder (DCD): 6 of whom had comorbid dyslexia; and 12 control children matched for age and IQ underwent…

  3. Comparing the Volumes of Rectangular Prisms

    ERIC Educational Resources Information Center

    Assuah, Charles K.; Wiest, Lynda R.

    2010-01-01

    Can middle-grades students determine which of two rectangular prisms has a larger volume? Can they do so without using a formula? Geometry, and particularly the concept of volume, is important in many subjects, such as physics and chemistry. Students greatly enhance their mathematics knowledge when they make generalizations and construct arguments…

  4. Reflecting Schmidt/Littrow Prism Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Page, N. A.; Shack, R. V.; Shannon, R. R.

    1985-01-01

    High resolution achieved with wide field of view. Imaging Spectrometer features off-axis reflecting optics, including reflecting "slit" that also serves as field flattener. Only refracting element is prism. By scanning slit across object or scene and timing out signal, both spectral and spatial information in scene are obtained.

  5. Boolean Operations with Prism Algebraic Patches

    PubMed Central

    Bajaj, Chandrajit; Paoluzzi, Alberto; Portuesi, Simone; Lei, Na; Zhao, Wenqi

    2009-01-01

    In this paper we discuss a symbolic-numeric algorithm for Boolean operations, closed in the algebra of curved polyhedra whose boundary is triangulated with algebraic patches (A-patches). This approach uses a linear polyhedron as a first approximation of both the arguments and the result. On each triangle of a boundary representation of such linear approximation, a piecewise cubic algebraic interpolant is built, using a C1-continuous prism algebraic patch (prism A-patch) that interpolates the three triangle vertices, with given normal vectors. The boundary representation only stores the vertices of the initial triangulation and their external vertex normals. In order to represent also flat and/or sharp local features, the corresponding normal-per-face and/or normal-per-edge may be also given, respectively. The topology is described by storing, for each curved triangle, the two triples of pointers to incident vertices and to adjacent triangles. For each triangle, a scaffolding prism is built, produced by its extreme vertices and normals, which provides a containment volume for the curved interpolating A-patch. When looking for the result of a regularized Boolean operation, the 0-set of a tri-variate polynomial within each such prism is generated, and intersected with the analogous 0-sets of the other curved polyhedron, when two prisms have non-empty intersection. The intersection curves of the boundaries are traced and used to decompose each boundary into the 3 standard classes of subpatches, denoted in, out and on. While tracing the intersection curves, the locally refined triangulation of intersecting patches is produced, and added to the boundary representation. PMID:21516262

  6. High-Power Prismatic Devices for Oblique Peripheral Prisms

    PubMed Central

    Peli, Eli; Bowers, Alex R.; Keeney, Karen; Jung, Jae-Hyun

    2016-01-01

    ABSTRACT Purpose Horizontal peripheral prisms for hemianopia provide field expansion above and below the horizontal meridian; however, there is a vertical gap leaving the central area (important for driving) without expansion. In the oblique design, tilting the bases of both prism segments toward the horizontal meridian moves the field expansion area vertically and centrally (closing the central gap) while the prisms remain in the peripheral location. However, tilting the prisms results also in a reduction of the lateral field expansion. Higher prism powers are needed to counter this effect. Methods We developed, implemented, and tested a series of designs aimed at increasing the prism power to reduce the central gap while maintaining wide lateral expansion. The designs included inserting the peripheral prisms into carrier lenses that included yoked prism in the opposite direction, combination of two Fresnel segments attached at the base and angled to each other (bi-part prisms), and creating Fresnel prism–like segments from nonparallel periscopic mirror pairs (reflective prisms). Results A modest increase in lateral power was achieved with yoked-prism carriers. Bi-part combination of 36Δ Fresnel segments provided high power with some reduction in image quality. Fresnel reflective prism segments have potential for high power with superior optical quality but may be limited in field extent or by interruptions of the expanded field. Extended apical scotomas, even with unilateral fitting, may limit the utility of very high power prisms. The high-power bi-part and reflective prisms enable a wider effective eye scanning range (more than 15 degrees) into the blind hemifield. Conclusions Conventional prisms of powers higher than the available 57Δ are limited by the binocular impact of a wider apical scotoma and a reduced effective eye scanning range to the blind side. The various designs that we developed may overcome these limitations and find use in various other

  7. Fresnel prisms and their effects on visual acuity and binocularity.

    PubMed Central

    Véronneau-Troutman, S

    1978-01-01

    1. The visual acuity with the Fresnel membrane prism is significantly less than that with the conventional prism of the same power for all prism powers from 12 delta through 30 delata at distance and from 15 delta through 30 delta at near. 2. The difference in the visual acuity between base up and base down, and between base in and base out, is not significantly different for either the Fresnel membrane prism or for the conventional prism. 3. For both Fresnel membrane prism and the conventional prism, the visual acuity when looking straight ahead. 4. Using Fresnel membrane prisms of the same power from different lots, the visual acuity varied significantly. The 30 delta prism caused the widest range in visual acuity. 5. When normal subjects are fitted with the higher powers of the Fresnel membrane prism, fusion and stereopsis are disrupted to such an extent that the use of this device to restore or to improve binocular vision in cases with large-angle deviations is seriously questioned. 6. Moreover, the disruption of fusion and stereopsis is abrupt and severe and does not parallel the decrease in visual acuity. The severely reduced ability to maintain fusion may be related to the optical aberrations, which, in turn, may be due to the molding process and the polyvinyl chloride molding material. 7. Through the flexibility of the membrane prism is a definite advantage, because of its proclivity to reduce visual acuity and increase aberrations its prescription for adults often must be limited to only one eye. 8. For the same reasons in the young child with binocular vision problems, the membrane prism presently available should be prescribed over both eyes only in powers less than 20 delta. When the membrane prism is to be used as a partial occluder (over one eye only), any power can be used. 9. The new Fresnel "hard" prism reduces visual acuity minimally and rarely disrupts binocularity, thus increasing the potential for prismotherapy to establish binocularity. This

  8. Self-referenced prism deflection measurement schemes with microradian precision

    SciTech Connect

    Olson, Rebecca; Paul, Justin; Bergeson, Scott; Durfee, Dallin S

    2005-08-01

    We have demonstrated several inexpensive methods that can be used to measure the deflection angles of prisms with microradian precision. The methods are self-referenced, where various reversals are used to achieve absolute measurements without the need of a reference prism or any expensive precision components other than the prisms under test. These techniques are based on laser interferometry and have been used in our laboratory to characterize parallel-plate beam splitters, penta prisms, right-angle prisms, and corner cube reflectors using only components typically available in an optics laboratory.

  9. Enamel prism morphology in molar teeth of small eutherian mammals.

    PubMed

    Dumont, E R

    1996-01-01

    Data summarizing enamel prism shape, size and spacing are reported for the molar enamel of 55 species of small eutherian mammals including primates, bats, tree shrews, flying lemurs, insectivorans and representatives of a variety of fossil families. Confocal photomicrographs reveal that the subsurface enamel of most species is characterized by arc-shaped prisms. The lack of a clear distinction between pattern 2 and pattern 3 prism configurations within single specimens suggests that the broad category "arc-shaped prisms" is the most appropriate descriptive grouping for these species. Of the total sample, three species exhibit only circular prisms while no evidence of prismatic enamel was found in two bats. Prism shape is not an informative phylogenetic character at the ordinal level for these morphologically primitive and relatively thin-enameled taxa. Significant differences between species in several prism size and spacing variables (central distance between prisms, prism diameter, prism area and the ratio of prism area to estimated ameloblast area) suggest the potential for further analyses of quantitative variation to document evolutionary relationships within or among family-level groups.

  10. [Integration design and diffraction characteristics analysis of prism-grating-prism].

    PubMed

    He, Tian-Bo; Bayanheshig; Li, Wen-Hao; Kong, Peng; Tang, Yu-Guo

    2014-01-01

    Prism-grating-prism (PGP) module is the important dispersing component in the hyper spectral imager. In order to effectively predict the distribution of diffraction efficiency of the whole PGP component and its diffraction characteristics before fabrication, a method of the PGP integration design is proposed. From the point of view of the volume phase holographic grating (VPHG) design, combined with the restrictive correlation between the various parameters of prisms and grating, we compiled the analysis software for calculating the whole PGP's diffraction efficiency. Furthermore, the effects of the structure parameters of prisms and grating on the PGP's diffraction characteristics were researched in detail. In particular we discussed the Bragg wavelength shift behaviour of the grating and a broadband PGP spectral component with high diffraction efficiency was designed for the imaging spectrometers. The result of simulation indicated that the spectral bandwidth of the PGP becomes narrower with the dispersion coefficient of prism 1 material decreasing; Bragg wavelength shift characteristics broaden the bandwidth of VPHG both spectrally and angularly, higher angular selectivity is desirable for selection requirements of the prism 1 material, and it can be easily tuned to achieve spectral bandwidth suitable for imaging PGP spectrograph; the vertex angle of prism 1, the film thickness and relative permittivity modulation of the grating have a significant impact on the distribution of PGP's diffraction efficiency, so precision control is necessary when fabrication. The diffraction efficiency of the whole PGP component designed by this method is no less than 50% in the wavelength range from 400 to 1000 nm, the specific design parameters have been given in this paper that have a certain reference value for PGP fabrication.

  11. Effects of Prism Eyeglasses on Objective and Subjective Fixation Disparity.

    PubMed

    Schroth, Volkhard; Joos, Roland; Jaschinski, Wolfgang

    2015-01-01

    In optometry of binocular vision, the question may arise whether prisms should be included in eyeglasses to compensate an oculomotor and/or sensory imbalance between the two eyes. The corresponding measures of objective and subjective fixation disparity may be reduced by the prisms, or the adaptability of the binocular vergence system may diminish effects of the prisms over time. This study investigates effects of wearing prisms constantly for about 5 weeks in daily life. Two groups of 12 participants received eyeglasses with prisms having either a base-in direction or a base-out direction with an amount up to 8 prism diopters. Prisms were prescribed based on clinical fixation disparity test plates at 6 m. Two dependent variables were used: (1) subjective fixation disparity was indicated by a perceived offset of dichoptic nonius lines that were superimposed on the fusion stimuli and (2) objective fixation disparity was measured with a video based eye tracker relative to monocular calibration. Stimuli were presented at 6 m and included either central or more peripheral fusion stimuli. Repeated measurements were made without the prisms and with the prisms after about 5 weeks of wearing these prisms. Objective and subjective fixation disparity were correlated, but the type of fusion stimulus and the direction of the required prism may play a role. The prisms did not reduce the fixation disparity to zero, but induced significant changes in fixation disparity with large effect sizes. Participants receiving base-out prisms showed hypothesized effects, which were concurrent in both types of fixation disparity. In participants receiving base-in prisms, the individual effects of subjective and objective effects were negatively correlated: the larger the subjective (sensory) effect, the smaller the objective (motor) effect. This response pattern was related to the vergence adaptability, i.e. the individual fusional vergence reserves.

  12. Effects of Prism Eyeglasses on Objective and Subjective Fixation Disparity

    PubMed Central

    Schroth, Volkhard; Joos, Roland; Jaschinski, Wolfgang

    2015-01-01

    In optometry of binocular vision, the question may arise whether prisms should be included in eyeglasses to compensate an oculomotor and/or sensory imbalance between the two eyes. The corresponding measures of objective and subjective fixation disparity may be reduced by the prisms, or the adaptability of the binocular vergence system may diminish effects of the prisms over time. This study investigates effects of wearing prisms constantly for about 5 weeks in daily life. Two groups of 12 participants received eyeglasses with prisms having either a base-in direction or a base-out direction with an amount up to 8 prism diopters. Prisms were prescribed based on clinical fixation disparity test plates at 6 m. Two dependent variables were used: (1) subjective fixation disparity was indicated by a perceived offset of dichoptic nonius lines that were superimposed on the fusion stimuli and (2) objective fixation disparity was measured with a video based eye tracker relative to monocular calibration. Stimuli were presented at 6 m and included either central or more peripheral fusion stimuli. Repeated measurements were made without the prisms and with the prisms after about 5 weeks of wearing these prisms. Objective and subjective fixation disparity were correlated, but the type of fusion stimulus and the direction of the required prism may play a role. The prisms did not reduce the fixation disparity to zero, but induced significant changes in fixation disparity with large effect sizes. Participants receiving base-out prisms showed hypothesized effects, which were concurrent in both types of fixation disparity. In participants receiving base-in prisms, the individual effects of subjective and objective effects were negatively correlated: the larger the subjective (sensory) effect, the smaller the objective (motor) effect. This response pattern was related to the vergence adaptability, i.e. the individual fusional vergence reserves. PMID:26431525

  13. Binocular rivalry with peripheral prisms used for hemianopia rehabilitation.

    PubMed

    Haun, Andrew M; Peli, Eli

    2014-09-01

    To determine the relative binocular signal strength of moving images that are peripherally viewed through a monocular field expansion prism as opposed to moving images viewed directly. We hypothesised that prism blur might make prism images predominate less than images viewed directly with the other eye. We employed the binocular rivalry paradigm to measure the relative binocular effectiveness of directly viewed vs prism images. Four normally-sighted subjects tracked the rivalrous visibility of opponent-coloured targets seen dichoptically in the same part of the retinal visual field, using monocular field expansion prisms to produce the dichoptic display. We analysed the effects of external signal strength (whether or not motion was present in either image), retinal position or eccentricity of the targets, and controlled for target saturation. We found that prism images predominate less than directly viewed images. When both eyes were presented with pattern in the dichoptic display, direct-to-prism predominance was 51%:31%. When only the direct view was presented with pattern, direct-to-prism predominance was 74%:12%; when only the prism view was presented with pattern, direct-to-prism predominance was 25%:58%. Dominance durations followed established binocular rivalry rules. The prism image in a monocular, peripheral field expansion prism is perceptually weaker than the corresponding direct image in the other eye. However, the prism image is still seen a significant proportion of the time, especially when no moving pattern is present in the direct view. We conclude that the rivalry ratio of the prism device is sufficiently effective for clinical applications. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

  14. Could Carlos Chagas' assumption on the relationship between goiter and chronic Chagas heart disease be correct? A historical reappraisal.

    PubMed

    Bestetti, Reinaldo B; Cardinalli-Neto, Augusto; Restini, Carolina B A; Couto, Lucelio B

    2016-01-01

    In 1910, Chagas divided the clinical manifestations of the chronic form of Chagas disease according to heart, Central Nervous System, and thyroid involvement, particularly the presence of goiter. Chagas emphasized the association of goiter with poor houses infested with kissing bugs, the similarity of the clinical picture with that of patients underwent partial thyroidectomy, and with the presence of thyroid sclerosis (inflammation) on histological examination. In addition, Chagas observed that all people living in poor houses infested by sucking bugs had goiter, contrasting with persons who lived in the same region, drinking the same water, but living in good houses, which did not have goiter. Furthermore, Chagas stressed the fact that people without any evidence of thyroid disease that migrated to live in poor houses in areas infested by sucking bugs developed thyroid disease some time later. Finally, and more importantly, Chagas emphasized the association of goiter with cardiac abnormalities in 80% of patients with chronic Chagas heart disease. Despite this, other authors working in different regions did not confirm such an association. A reappraisal of data from a work published in 1949 clearly shows that the presence of goiter was statistically associated with chronic Chagas heart disease and with chronic Chagas disease. Our paper highlights once more the grandiosity of Chagas' work, which has been proved to be correct even in the history of goiter, and justifies our claim for a posthumous Nobel Prize inasmuch as his work was not perceived by the Karolinska Institute.

  15. Total internal reflection photonic crystal prism.

    PubMed

    Schonbrun, Ethan; Abashin, Maxim; Blair, John; Wu, Qi; Park, Wounjhang; Fainman, Yeshaiahu; Summers, Christopher J

    2007-06-25

    An integrated total internal reflection prism is demonstrated that generates a transversely localized evanescent wave along the boundary between a photonic crystal and an etched out trench. The reflection can be described by either the odd symmetry of the Bloch wave or a tangential momentum matching condition. In addition, the Bloch wave propagates through the photonic crystal in a negative refraction regime, which manages diffraction within the prism. A device with three input channels has been fabricated and tested that illuminates different regions of the reflection interface. The reflected wave is then sampled by a photonic wire array, where the individual channels are resolved. Heterodyne near field scanning optical microscopy is used to characterize the spatial phase variation of the evanescent wave and its decay constant.

  16. PRISM: protein interactions by structural matching.

    PubMed

    Ogmen, Utkan; Keskin, Ozlem; Aytuna, A Selim; Nussinov, Ruth; Gursoy, Attila

    2005-07-01

    Prism (http://gordion.hpc.eng.ku.edu.tr/prism) is a website for protein interface analysis and prediction of putative protein-protein interactions. It is composed of a database holding protein interface structures derived from the Protein Data Bank (PDB). The server also includes summary information about related proteins and an interactive protein interface viewer. A list of putative protein-protein interactions obtained by running our prediction algorithm can also be accessed. These results are applied to a set of protein structures obtained from the PDB at the time of algorithm execution (January 2004). Users can browse through the non-redundant dataset of representative interfaces on which the prediction algorithm depends, retrieve the list of similar structures to these interfaces or see the results of interaction predictions for a particular protein. Another service provided is interactive prediction. This is done by running the algorithm for user input structures.

  17. PRISM3 DOT1 Atlantic Basin Reconstruction

    USGS Publications Warehouse

    Dowsett, Harry; Robinson, Marci; Dwyer, Gary S.; Chandler, Mark; Cronin, Thomas

    2006-01-01

    PRISM3 DOT1 (Pliocene Research, Interpretation and Synoptic Mapping 3, Deep Ocean Temperature 1) provides a three-dimensional temperature reconstruction for the mid-Pliocene Atlantic basin, the first of several regional data sets that will comprise a global mid-Pliocene reconstruction. DOT1 is an alteration of modern temperature values for the Atlantic Ocean in 4 degree x 5 degree cells in 13 depth layers for December 1 based on Mg/Ca-derived BWT estimates from seventeen DSDP and ODP Sites and SST estimates from the PRISM2 reconstruction (Dowsett et al., 1999). DOT1 reflects a vaguely modern circulation system, assuming similar processes of deep-water formation; however, North Atlantic Deep Water (NADW) production is increased, and Antarctic Bottom Water (AABW) production is decreased. Pliocene NADW was approximately 2 degreesC warmer than modern temperatures, and Pliocene AABW was approximately 0.3 degreesC warmer than modern temperatures.

  18. Opera: Objective-Prism Reduction Package

    NASA Astrophysics Data System (ADS)

    García Dabó, C. E.; Gallego, J.

    1998-06-01

    Surveys of star-forming galaxies are of vital importance to constrain galactic evolution theories. One of the most successful searching methods is the objective-prism (OP) technique, which can register thousands of low resolution spectra in large areas. The UCM-CIDA (Universidad Complutense de Madrid-Centro de Investigación F. J. Duarte) project expects to cover 150 square degrees and detect ˜ 2000 Hα emission line galaxies.

  19. Prisms to Shift Pain Away: Pathophysiological and Therapeutic Exploration of CRPS with Prism Adaptation

    PubMed Central

    Volckmann, Pierre; Jacquin-Courtois, Sophie

    2016-01-01

    Complex Regional Pain Syndrome (CRPS) is an invalidating chronic condition subsequent to peripheral lesions. There is growing consensus for a central contribution to CRPS. However, the nature of this central body representation disorder is increasingly debated. Although it has been repeatedly argued that CRPS results in motor neglect of the affected side, visual egocentric reference frame was found to be deviated toward the pain, that is, neglect of the healthy side. Accordingly, prism adaptation has been successfully used to normalize this deviation. This study aimed at clarifying whether 7 CRPS patients exhibited neglect as well as exploring the pathophysiological mechanisms of this manifestation and of the therapeutic effects of prism adaptation. Pain and quality of life, egocentric reference frames (visual and proprioceptive straight-ahead), and neglect tests (line bisection, kinematic analyses of motor neglect and motor extinction) were repeatedly assessed prior to, during, and following a one-week intense prism adaptation intervention. First, our results provide no support for visual and motor neglect in CRPS. Second, reference frames for body representations were not systematically deviated. Third, intensive prism adaptation intervention durably ameliorated pain and quality of life. As for spatial neglect, understanding the therapeutic effects of prism adaptation deserves further investigations. PMID:27668094

  20. Prisms to Shift Pain Away: Pathophysiological and Therapeutic Exploration of CRPS with Prism Adaptation.

    PubMed

    Christophe, Laure; Chabanat, Eric; Delporte, Ludovic; Revol, Patrice; Volckmann, Pierre; Jacquin-Courtois, Sophie; Rossetti, Yves

    Complex Regional Pain Syndrome (CRPS) is an invalidating chronic condition subsequent to peripheral lesions. There is growing consensus for a central contribution to CRPS. However, the nature of this central body representation disorder is increasingly debated. Although it has been repeatedly argued that CRPS results in motor neglect of the affected side, visual egocentric reference frame was found to be deviated toward the pain, that is, neglect of the healthy side. Accordingly, prism adaptation has been successfully used to normalize this deviation. This study aimed at clarifying whether 7 CRPS patients exhibited neglect as well as exploring the pathophysiological mechanisms of this manifestation and of the therapeutic effects of prism adaptation. Pain and quality of life, egocentric reference frames (visual and proprioceptive straight-ahead), and neglect tests (line bisection, kinematic analyses of motor neglect and motor extinction) were repeatedly assessed prior to, during, and following a one-week intense prism adaptation intervention. First, our results provide no support for visual and motor neglect in CRPS. Second, reference frames for body representations were not systematically deviated. Third, intensive prism adaptation intervention durably ameliorated pain and quality of life. As for spatial neglect, understanding the therapeutic effects of prism adaptation deserves further investigations.

  1. Risley prism universal pointing system (RPUPS)

    NASA Astrophysics Data System (ADS)

    Dixon, John; Engel, James R.; Vaillancourt, Robert; Schwarze, Craig; Potter, Kevin

    2015-09-01

    OPTRA is currently developing a Risley Prism Universal Pointing System (RPUPS): a highly customizable cued beamsteering system. The RPUPS consists of a visible or infrared cueing imager co-aligned with an optical beam steering system's pointing-field-of-regard. The cueing imager is used to identify a region-of-interest within its wide field-of-view, via a wireless tablet device. The tablet user can choose to manually or automatically, identify and track regions-of-interest. The optical beam steering system uses a matched pair of Risley Prisms to direct an interrogating optical system's instantaneous-field-of-view onto the identified region-of-interest. The tablet updates the user with real time information from both the cueing imager and the interrogating optical system. Risley prism material and geometry choices provide operating wavelength, aperture size, and field-of-regard flexibility for this front-end pointing component. Back-end components may be receive-only, transmit-only, or transmit/receive combinations. The flexibility of the RPUPS allows for mission specific customization where applications include but are not limited to: synthetic foveated imaging, spectroscopic probes and laser (LIDAR) ranging and tracking. This paper will focus on the design and anticipated applications of the RPUPS.

  2. Evaluations of 1990 PRISM design revisions

    SciTech Connect

    Van Tuyle, G.J.; Slovik, G.C.; Chan, B.C.; Aronson, A.L.; Kennett, R.J.

    1992-03-01

    Analyses of the 1990 version of the PRISM Advanced Liquid Metal Reactor (ALMR) design are presented and discussed. Most of the calculations were performed using BNL computer codes, particularly SSC and MINET. In many cases, independent BNL calculations were compared against analyses presented by General Electric when they submitted the PRISM design revisions for evaluation by the Nuclear Regulatory Commission (NRC). The current PRISM design utilizes the metallic fuel developed by Argonne National Laboratory (ANL) which facilitates the passive/``inherent`` shutdown mechanism that acts to shut down reactor power production whenever the system overheats. There are a few vulnerabilities in the passive shutdown, with the most worrisome being the positive feedback from sodium density decreases or sodium voiding. Various postulated unscrammed events were examined by GE and/or BNL, and much of the analysis discussed in this report is focused on this category of events. For the most part, the BNL evaluations confirm the information submitted by General Electric. The principal areas of concern are related to the performance of the ternary metal fuel, and may be resolved as ANL continues with its fuel development and testing program.

  3. The effects of vertical yoked prisms on gait.

    PubMed

    Errington, Jodie A; Menant, Jasmine C; Suttle, Catherine M; Bruce, Jessica; Asper, Lisa J

    2013-06-10

    To investigate the influence of base down (BD) and base up (BU) yoked prism wear on gait. Gait was assessed in 31 young healthy adults (mean age, 24.0 ± 5.1 years) during and after wearing 5 prism diopter ((Δ)) BU yoked prisms, 5(Δ) BD yoked prisms, and plano (PL) (zero power; control condition) lenses, worn in a pseudorandom order. Velocity; cadence; step length; double support phase; step width; and variability in step time, step width, step length, and swing time were measured as participants walked at a freely chosen walking speed along a 5.3-m electronic mat placed in the center of a 7.5-m walkway. Gait parameters were analyzed for each viewing condition before, during, and after prism wear. BD yoked prisms, when compared with PL, led to slower velocity, lower cadence, decreased step length, and increased step time variability (P ≤ 0.001) These gait parameters did not significantly differ between BU yoked prisms and PL lenses (P > 0.05). Measurements taken immediately on removal did not differ from those taken after a time delay of 5 minutes. BD yoked prisms affected gait in young healthy adults walking across an unobstructed path at their freely chosen walking speed, in that participants adopted a slower, apparently more cautious gait pattern; BU yoked prisms did not significantly affect gait. The effect of BD prism on gait may be due in part to a perception of increased height.

  4. Flavonoids and Chagas' Disease: The Story So Far!

    PubMed

    Nabavi, Seyed Fazel; Sureda, Antoni; Daglia, Maria; Izadi, Morteza; Rastrelli, Luca; Nabavi, Seyed Mohammad

    2017-01-01

    Chagas disease is one of the major health problems in Central and South America, which is caused by the parasitic protozoa, Trypanosoma cruzi. It is commonly transmitted by members of blood-sucking subfamily Triatominae. Chagas disease is associated with cardiac and gastrointestinal manifestations. Up to now, there are no effective vaccines for treatment of Chagas disease and benznidazole and nifurtimox are the only effective anti-Chagas drugs that cause different adverse and side effects. Therefore, much attention has been paid to natural products as novel therapeutic strategies for Chagas disease and its manifestations. Nowadays, some flavonoids could be considered as effective and safe bioactive natural products with potential anti-Chagas activity. Despite the increasing evidence, there is lack of review papers regarding the beneficial effects of flavonoids against Chagas disease and its manifestations. The aim of this paper is to review the available scientific data on the beneficial effects of flavonoids on Chagas disease and its manifestations published over the past two decades. Moreover, we provide an overview on etiology, transmission, epidemiology, clinical manifestations, and current treatment protocols of Chagas disease.

  5. Compound prism design principles, III: linear-in-wavenumber and optical coherence tomography prisms

    PubMed Central

    Hagen, Nathan; Tkaczyk, Tomasz S.

    2011-01-01

    We extend the work of the first two papers in this series [Appl. Opt. 50, 4998–5011 (2011), Appl. Opt. 50, 5012–5022 (2011)] to design compound prisms for linear-in-wavenumber dispersion, especially for application in spectral domain optical coherence tomography (OCT). These dispersive prism designs are believed to be the first to meet the requirements of high resolution OCT systems in direct-view geometry, where they can be used to shrink system size, to improve light throughput, to reduce stray light, and to reduce errors resulting from interpolating between wavelength- and wavenumber-sampled domains. We show prism designs that can be used for thermal sources or for wideband superluminescent diodes centered around wavelengths 850, 900, 1300, and 1375 nm. PMID:22423147

  6. A comparison of applanation tonometry using conventional reusable goldmann prisms and disposable prisms.

    PubMed

    Tsai, Andrew S H; How, Alicia C; Su, Daniel H W; Lee, Kelvin Y; Wong, Tina T; Perera, Shamira A

    2014-01-01

    To determine the agreement between intraocular pressure (IOP) measurements using conventional Goldmann applanation tonometry (GAT) and Tonosafe disposable prisms, and also to provide a comprehensive cost analysis of the use of both types of prisms : In this prospective observational study, 198 eyes of 100 glaucoma patients had their IOPs measured by 5 consultant ophthalmologists. Data were analyzed using the Bland-Altman method of differences, and correlation was measured using the Pearson coefficient. An analysis of the cost incurred using the 2 methods over a 6-month period was performed. The majority were Chinese (82%), with a male preponderance (57%). The range of IOPs as measured by GAT was 4 to 34 mm Hg. Using the Bland-Altman method to compare GAT and disposable prisms, the bias was 0.2 mm Hg. Tonosafe overestimated the IOP by 0.2 mm Hg in the right eye and underestimated it by 0.2 mm Hg in the left eye. The Tonosafe IOP correlated well with GAT, with a Pearson coefficient of correlation(r) of 0.91 (P<0.0005) for the right eye and 0.92 (P<0.0005) for the left eye, respectively. For those with GAT IOP≥21 mm Hg (n=26), Tonosafe underestimated the IOP by 0.35 mm Hg. The cost incurred by Tonosafe prisms was approximately 8 times that of GAT, but the cost differential reverses when GAT had to be replaced after every 100 cycles of disinfection. We found a good correlation between Tonosafe prisms and conventional GAT in measuring the IOP. Tonosafe prisms may be of use, especially if the risk of transmission of infection is high. However, cost may limit its more widespread use.

  7. Immunosensor for the diagnosis of Chagas' disease.

    PubMed

    Ferreira, Antonio Aparecido Pupim; Colli, Walter; da Costa, Paulo Inácio; Yamanaka, Hideko

    2005-07-15

    Trypanosoma cruzi proteins from epimastigote membranes, herein referred as antigens, have been used for the construction of an amperometric immunosensor for serological diagnosis of Chagas' disease. The proteins used had a molecular mass ranging from 30 to 100 kDa. The gold electrode was treated with cysteamine and glutaraldehyde prior to antigen immobilization. Antibodies present in the serum of patients with Chagas' disease were captured by the immobilized antigens and the affinity interaction was monitored by chronoamperometry at a potential of -400 mV (versus Ag pseudo-reference electrode) using peroxidase-labeled IgG conjugate and hydrogen peroxide, iodide substrate. The incubation time to allow maximum antigen-antibody and antibody-peroxidase-labeled IgG interactions was 20 min with a reactivity threshold at -0.104 microA.

  8. The Southern Cone Initiative against Chagas disease.

    PubMed

    Schofield, C J; Dias, J C

    1999-01-01

    Chagas disease (also known as American trypanosomiasis) is now ranked as the most serious parasitic disease of the Americas, with an economic impact far outranking the combined effects of other parasitic diseases such as malaria, schistosomiasis and leishmaniasis. Although the chronic infection remains virtually incurable, transmission can be halted by eliminating the domestic insect vectors and screening blood donors to avoid transfusional transmission. In line with this strategy, governments of the six Southern Cone countries (Argentina, Bolivia, Brazil, Chile, Paraguay and Uruguay) launched in 1991 an ambitious initiative to control Chagas disease through elimination of the main vector, Triatoma infestans, and large-scale screening of blood donors. Now at its mid-point, the programme has achieved remarkable success, with transmission halted over vast areas of the previously endemic regions. Well over 2 million rural houses have been sprayed to eliminate T. infestans, and the programme has already shown significant economic rates of return in addition to the medical and social benefits.

  9. Natural Chagas Disease in Four Baboons

    PubMed Central

    Williams, Jeff T.; Dick, Edward J.; VandeBerg, John L.; Hubbard, Gene B.

    2010-01-01

    Background Chagas disease is common in Central and South America and the southern United States. The causative agent is Trypanosoma cruzi (T cruzi, Order Kinetoplastida, Family Trypanosomatidae), a kinetoplastid protozoan parasite of humans and other vertebrates. It is a serious public health issue and the leading cause of heart disease and cardiovascular death in Central and South America. In 1984 a colony baboon was discovered to be infected with T cruzi. Methods Since the initial diagnosis was made by microscopic observation of the amastigote forms of T. cruzi in myocardial fibers, T. cruzi amastigotes have been identified in three additional baboons. Results The primary findings were similar in all four baboons and were congestive heart failure with edema of dependent areas, hydrothorax, hydropericardium, and multifocal to diffuse lymphoplasmacytic myocarditis. Conclusions A baboon animal model of Chagas disease could contribute significantly to the development of therapies for the disease in humans. PMID:18671766

  10. Palm trees and Chagas' disease in Panama.

    PubMed

    Whitlaw, J T; Chaniotis, B N

    1978-09-01

    An ecological survey of triatomines in the sylvan ecosystem of the Canal Zone and selected sites in Panama disclosed for the first time a close association of Rhodnius pullescens and Triatoma dimidiata, the two most important vector species of Chagas' disease in Panama, with a single species of a widely distributed palm tree, Scheelea zonensis. This association may explain why Chagas' disease is prevalent in certain rural communities in Central Panama and rare in others. An immense focus of zoonotic Trypanosoma cruzi infection exists in the forests of the Canal Zone with presence of large populations of triatomines, associated with scheelea zonensis and other yet undescribed microhabitats, and high (50--60%) trypanosome infections in all of the major triatomine species. Common opossums, anteaters, and spiny rats seem to be the principal animal reservoirs of T. cruzi in this complex and relatively undisturbed ecosystem.

  11. Ticks, ivermectin, and experimental Chagas disease.

    PubMed

    Dias, João Carlos Pinto; Schofield, Christopher J; Machado, Evandro Mm; Fernandes, Alexandre José

    2005-12-01

    Following an infestation of dogticks in kennels housing dogs used for long-term studies of the pathogenesis of Chagas disease, we examined the effect of ivermectin treatment on the dogs, ticks, trypanosome parasites, and also on triatomine vectors of Chagas disease. Ivermectin treatment was highly effective in eliminating the ticks, but showed no apparent effect on the dogs nor on their trypanosome infection. Triatominae fed on the dogs soon after ivermectin treatment showed high mortality, but this effect quickly declined for bugs fed at successive intervals after treatment. In conclusion, although ivermectin treatment may have a transient effect on peridomestic populations of Triatominae, it is not the treatment of choice for this situation. The study also showed that although the dogticks could become infected with Trypanosoma cruzi, this only occurred when feeding on dogs in the acute phase of infection, and there was no evidence of subsequent parasite development in the ticks.

  12. Apical aneurysm of Chagas's heart disease.

    PubMed Central

    Oliveira, J S; Mello De Oliveira, J A; Frederigue, U; Lima Filho, E C

    1981-01-01

    A retrospective study of Chagas's heart disease was carried out by a review of necropsy reports with special reference to the lesion known as the apical aneurysm. It was concluded that this lesion was more frequent in men, was unrelated to age, and was unrelated to heart weight. Patients dying of the cardiac consequences of Chagas's cardiomyopathy were more likely to have an apical aneurysm than those whose death was unrelated to the disease but the mode of death (sudden, or with heart failure) was unconnected with its presence. Transillumination from within the ventricle at necropsy was not only useful in demonstrating the aneurysm but also showed areas of myocardial thinning elsewhere. Thrombosis within the lesion was frequent. The aetiology of the apical aneurysm is discussed and it is concluded that while ischaemia, inflammation, thrombosis, and mechanical factors may produce and localise this lesion, the underlying cause is the basic pathogenetic process-parasympathetic nerve cell destruction. Images PMID:7295439

  13. Fatal acute Chagas Disease in a Chimpanzee

    DTIC Science & Technology

    2009-08-01

    Fatal Acute Chagas Disease in a Chimpanzee Yugendar R. Bommineni1, Edward J. Dick Jr.1, J. Scot Estep2, John L. Van de Berg1, and Gene B. Hubbard1...species and several insect vectors demonstrating a wide host distribution and low host specificity. Methods—A 23 year old male chimpanzee died acutely and... chimpanzee . Keywords Ape; nonhuman primate; protozoa; fatal case; Trypanosoma cruzi Introduction CD or American trypanosomiasis is caused by TC, a

  14. Chagas disease in the immunosuppressed host.

    PubMed

    Bern, Caryn

    2012-08-01

    This review examines recent literature on Chagas disease in the immunosuppressed host. Chagas disease in immunosuppressed patients may represent acute transmission in an organ recipient, or reactivation of chronic infection in an HIV-infected individual or patient receiving cardiac transplantation for Chagas cardiomyopathy. Transplantation of the kidney or liver from an infected donor resulted in transmission in 18-19 and 29%, respectively. Prospective monitoring usually detects acute infection before symptom onset; early treatment is highly effective. In heart transplant patients, reactivation symptoms include fever, myocarditis and skin lesions, and may mimic rejection. Approximately 20% of HIV- Trypanosoma cruzi infected patients experience reactivation; manifestations include meningoencephalitis and/or myocarditis. Transplantation of the heart from a T. cruzi-infected donor is contraindicated; use of other organs can be considered. Guidelines recommend prospective monitoring rather than prophylactic treatment in recipients. Posttransplant monitoring for acute infection or reactivation relies on PCR, culture and microscopy of blood specimens regularly for at least 6 months. Treatment employs standard courses of benznidazole or nifurtimox, and immune reconstitution for the HIV-coinfected patient. Case reports suggest some HIV-T. cruzi-infected patients may benefit from secondary prophylaxis, but more data are needed to determine efficacy and specific regimens.

  15. [Chagas disease (American trypanosomiasis) in France].

    PubMed

    Salamanca-Dejour, D; Blanchet, D; Aznar, C; La Ruche, G; Jeannel, D; Gastellu-Etchegorry, M

    2012-08-01

    Chagas disease is an anthropozoonotic infection caused by Trypanosoma cruzi, transmitted by a hematophagous triatomine insect vector belonging to the Reduviidae family, while taking a blood meal. There is a large reservoir of wild and domestic mammals. Human contamination may come via vectorial, transplacental, and digestive routes, blood transfusion, organ or tissue transplantation, and by accident. The disease has two phases. The acute phase, oligosymptomatic, is frequently undiagnosed. It is followed by a chronic phase. Most of the infected patients remain asymptomatic all life-long. But 10 or 25 years later, one third of infected patients present with cardiac or digestive complications. Chagas disease is endemic in Latin America, from Mexico to Argentina. In French Guyana, the prevalence of the infection was estimated at 0.25% and 0.5% (from 500 to 1000 infected patients) on blood samples collected from 1992 to 1998. In 2000 and 2009, 192 cases were diagnosed. In this district, there is no established domestic vector and the transmission risk is low. The vector is very easily found in forest habitats and even in the peridomestic persistent forest, with an infection rate of 46 to 86%. Vectorial eradication is impossible. Fighting against Chagas disease in French Guyana relies more on individual protection, control of blood transfusion, prevention of mother-to-child transmission, diagnosis, and treatment of infected patients than on vectorial control. Copyright © 2012. Published by Elsevier SAS.

  16. Paleoparasitology of Chagas disease--a review.

    PubMed

    Araújo, Adauto; Jansen, Ana Maria; Reinhard, Karl; Ferreira, Luiz Fernando

    2009-07-01

    One hundred years since the discovery of Chagas disease associated with Trypanosoma cruzi infection, growing attention has focused on understanding the evolution in parasite-human host interaction. This interest has featured studies and results from paleoparasitology, not only the description of lesions in mummified bodies, but also the recovery of genetic material from the parasite and the possibility of analyzing such material over time. The present study reviews the evidence of Chagas disease in organic remains excavated from archeological sites and discusses two findings in greater detail, both with lesions suggestive of chagasic megacolon and confirmed by molecular biology techniques. One of these sites is located in the United States, on the border between Texas and Mexico and the other in state of Minas Gerais, in the Brazilian cerrado (savannah). Dated prior to contact with Europeans, these results confirm that Chagas disease affected prehistoric human groups in other regions outside the Andean altiplanos and other transmission areas on the Pacific Coast, previously considered the origin of T. cruzi infection in the human host.

  17. Peripheral prism glasses: effects of moving and stationary backgrounds.

    PubMed

    Shen, Jieming; Peli, Eli; Bowers, Alex R

    2015-04-01

    Unilateral peripheral prisms for homonymous hemianopia (HH) expand the visual field through peripheral binocular visual confusion, a stimulus for binocular rivalry that could lead to reduced predominance and partial suppression of the prism image, thereby limiting device functionality. Using natural-scene images and motion videos, we evaluated whether detection was reduced in binocular compared with monocular viewing. Detection rates of nine participants with HH or quadranopia and normal binocularity wearing peripheral prisms were determined for static checkerboard perimetry targets briefly presented in the prism expansion area and the seeing hemifield. Perimetry was conducted under monocular and binocular viewing with targets presented over videos of real-world driving scenes and still frame images derived from those videos. With unilateral prisms, detection rates in the prism expansion area were significantly lower in binocular than in monocular (prism eye) viewing on the motion background (medians, 13 and 58%, respectively, p = 0.008) but not the still frame background (medians, 63 and 68%, p = 0.123). When the stimulus for binocular rivalry was reduced by fitting prisms bilaterally in one HH and one normally sighted subject with simulated HH, prism-area detection rates on the motion background were not significantly different (p > 0.6) in binocular and monocular viewing. Conflicting binocular motion appears to be a stimulus for reduced predominance of the prism image in binocular viewing when using unilateral peripheral prisms. However, the effect was only found for relatively small targets. Further testing is needed to determine the extent to which this phenomenon might affect the functionality of unilateral peripheral prisms in more real-world situations.

  18. Magnetic prism alignment system for measuring large-angle strabismus.

    PubMed

    Bishop, John Edward

    2014-02-01

    Prismatic measurement of large-angle strabismus requires the simultaneous use of two or more prisms for neutralization. To facilitate the clinical measurement of large-angle strabismus a new prism system was designed utilizing a flat plate and a ferrous metal surface coupled with prisms containing rare earth magnets implanted in their base and bottom surfaces. Copyright © 2014 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.

  19. Peripheral Prism Glasses: Effects of Moving and Stationary Backgrounds

    PubMed Central

    Shen, Jieming; Peli, Eli; Bowers, Alex R.

    2015-01-01

    Purpose Unilateral peripheral prisms for homonymous hemianopia (HH) expand the visual field through peripheral binocular visual confusion, a stimulus for binocular rivalry that could lead to reduced predominance (partial local suppression) of the prism image and limit device functionality. Using natural-scene images and motion videos, we evaluated whether detection was reduced in binocular compared to monocular viewing. Methods Detection rates of nine participants with HH or quadranopia and normal binocularity wearing peripheral prisms were determined for static checkerboard perimetry targets briefly presented in the prism expansion area and the seeing hemifield. Perimetry was conducted under monocular and binocular viewing with targets presented over videos of real-world driving scenes and still frame images derived from those videos. Results With unilateral prisms, detection rates in the prism expansion area were significantly lower in binocular than monocular (prism eye) viewing on the motion background (medians 13% and 58%, respectively, p = 0.008), but not the still frame background (63% and 68%, p = 0.123). When the stimulus for binocular rivalry was reduced by fitting prisms bilaterally in 1 HH and 1 normally-sighted subject with simulated HH, prism-area detection rates on the motion background were not significantly different (p > 0.6) in binocular and monocular viewing. Conclusions Conflicting binocular motion appears to be a stimulus for reduced predominance of the prism image in binocular viewing when using unilateral peripheral prisms. However, the effect was only found for relatively small targets. Further testing is needed to determine the extent to which this phenomenon might affect the functionality of unilateral peripheral prisms in more real-world situations. PMID:25785533

  20. Peripheral prism glasses: effects of dominance, suppression, and background.

    PubMed

    Ross, Nicole C; Bowers, Alex R; Peli, Eli

    2012-09-01

    Unilateral peripheral prisms for homonymous hemianopia (HH) place different images on corresponding peripheral retinal points, a rivalrous situation in which local suppression of the prism image could occur and thus limit device functionality. Detection with peripheral prisms has primarily been evaluated using conventional perimetry, where binocular rivalry is unlikely to occur. We quantified detection over more visually complex backgrounds and examined the effects of ocular dominance. Detection rates of eight participants with HH or quadranopia and normal binocularity wearing unilateral peripheral prism glasses were determined for static perimetry targets briefly presented in the prism expansion area (in the blind hemifield) and the seeing hemifield, under monocular and binocular viewing, over uniform gray and more complex patterned backgrounds. Participants with normal binocularity had mixed sensory ocular dominance, demonstrated no difference in detection rates when prisms were fitted on the side of the HH or the opposite side (p > 0.2), and had detection rates in the expansion area that were not different for monocular and binocular viewing over both backgrounds (p > 0.4). However, two participants with abnormal binocularity and strong ocular dominance demonstrated reduced detection in the expansion area when prisms were fitted in front of the non-dominant eye. We found little evidence of local suppression of the peripheral prism image for HH patients with normal binocularity. However, in cases of strong ocular dominance, consideration should be given to fitting prisms before the dominant eye. Although these results are promising, further testing in more realistic conditions including image motion is needed.

  1. Wollaston prism phase-stepping point diffraction interferometer and method

    DOEpatents

    Rushford, Michael C.

    2004-10-12

    A Wollaston prism phase-stepping point diffraction interferometer for testing a test optic. The Wollaston prism shears light into reference and signal beams, and provides phase stepping at increased accuracy by translating the Wollaston prism in a lateral direction with respect to the optical path. The reference beam produced by the Wollaston prism is directed through a pinhole of a diaphragm to produce a perfect spherical reference wave. The spherical reference wave is recombined with the signal beam to produce an interference fringe pattern of greater accuracy.

  2. An Improved Prism for Use in Laser Resonators

    DTIC Science & Technology

    1981-08-01

    at an angle 6 to the X axis shown in figure 1, will emerge from the prism with its plane of polarisation rotated by 20. A Porno pritm operates a little... differently from the compound TIR prism in that only two total internal reflections occur and the phase shifts occurring at each reflection add...effective reflectivity is plotted in figure 3 for the compound ’TIR prism as well as for various Porro prisms of different refractive indlces(ref.l). It is

  3. Review on the use of Fresnel prism in low vision

    NASA Astrophysics Data System (ADS)

    Woo, George C.

    1992-08-01

    Fresnel prisms are often prescribed for visual field defects in low vision patients. These prisms are made of optical polyvinyl chloride (PVC) and this material increases chromatic dispersion and produces a loss of contrast. In this presentation, the effect of chromatic dispersion on contrast sensitivity is determined. It has been verified that loss of contrast sensitivity is greater at higher spatial frequencies with Fresnel prisms than with glass prisms of the same power. Above 10 prism diopters, Fresnel prisms reduce both contrast sensitivity and visual acuity substantially. However, low vision patients with visual field losses appear not to be affected due to their sometimes very low remaining contrast sensitivity and visual acuity. In the presence of both blurred and diplopic vision, a case report indicating the use of prisms in alleviating diplopia caused by trauma is presented. In spite of a reduction in visual acuity and contrast sensitivity, the patient preferred to have the Fresnel prism on his spectacle lenses for distance viewing. Diplopia appeared to cause more annoyance than the reduction of acuity and contrast sensitivity due to the Fresnel prism.

  4. Prism fingerprint sensor that uses a holographic optical element.

    PubMed

    Bahuguna, R D; Corboline, T

    1996-09-10

    A prism fingerprint sensor is described that uses a holographic grating glued to a right-angled prism. A light source normally illuminates the hypotenuse side of the prism with the finger pressed against the grating. The ridges and valleys of the finger are sensed on the basis of the principle of total internal reflection. The grating is used essentially to correct the distortion usually present with prism sensors. The quality of the fingerprint is very good: the pores on the ridges can be seen.

  5. Biomarkers and mortality in severe Chagas cardiomyopathy.

    PubMed

    Sherbuk, Jacqueline E; Okamoto, Emi E; Marks, Morgan A; Fortuny, Enzo; Clark, Eva H; Galdos-Cardenas, Gerson; Vasquez-Villar, Angel; Fernandez, Antonio B; Crawford, Thomas C; Do, Rose Q; Flores-Franco, Jorge Luis; Colanzi, Rony; Gilman, Robert H; Bern, Caryn

    2015-09-01

    Chagas cardiomyopathy is a chronic sequela of infection by the parasite, Trypanosoma cruzi. Advanced cardiomyopathy is associated with a high mortality rate, and clinical characteristics have been used to predict mortality risk. Though multiple biomarkers have been associated with Chagas cardiomyopathy, it is unknown how these are related to survival. This study aimed to identify biomarkers associated with mortality in individuals with severe Chagas cardiomyopathy in an urban Bolivian hospital. The population included individuals with and without T. cruzi infection recruited in an urban hospital in Santa Cruz, Bolivia. Baseline characteristics, electrocardiogram findings, medications, and serum cardiac biomarker levels (B-type natriuretic peptide [BNP], N-terminal pro-B-type natriuretic peptide [NT-proBNP], creatine kinase-myocardial band [CK-MB], troponin I, matrix metalloproteinase [MMP]-2, MMP-9, tissue inhibitor of metalloproteinases [TIMP] 1 and 2, transforming growth factor [TGF] beta 1 and 2) were ascertained. Echocardiograms were performed on those with cardiac symptoms or electrocardiogram abnormalities at baseline. Participants were contacted approximately 1 year after initial evaluation; deaths were reported by family members. Receiver-operating characteristic curves (ROC) were used to optimize cutoff values for each marker. For markers with area under the curve (AUC) >0.55, Cox proportional hazards models were performed to determine the hazards ratio (HR) and 95% confidence interval (CI) for the association of each marker with mortality. The median follow-up time was 14.1 months (interquartile range 12.5, 16.7). Of 254 individuals with complete cardiac data, 220 (87%) had follow-up data. Of 50 patients with severe Chagas cardiomyopathy at baseline, 20 (40%) had died. Higher baseline levels of BNP (HR: 3.1, 95% CI: 1.2 to 8.4), NT-proBNP (HR: 4.4, 95% CI: 1.8 to 11.0), CK-MB (HR: 3.3, 95% CI: 1.3 to 8.0), and MMP-2 (HR: 4.2, 95% CI: 1.5 to 11.8) were

  6. Prism. Volume 2, Number 1, December 2010

    DTIC Science & Technology

    2010-12-01

    modern era CIvIlIAn ReSPonSe CoRPS 24 | FeatuReS PRISM 2, no. 1 region I represent is a focal point for higher education . We have the Naval... educating , and using the new tool. The active corps must be recruited to the maximum autho- rized number of 250. All the ancillary compo- nents necessary to...Nations (UN) field missions, or nongovern- mental relief or development agencies. They need the best education and training possible for the complex and

  7. Modified PRISM theory for confined polymers.

    PubMed

    Xu, Mengjin; Zhang, Chen; Du, Zhongjie; Mi, Jianguo

    2012-11-14

    We propose a modified polymer reference interaction site model (PRISM) to describe the interfacial density profiles of polymers in contact with planar and curved solid surfaces. In the theoretical approach, a bridge function derived from density functional method is included. In description of hard-sphere polymer at planar and curved surfaces with an arbitrary external field, the effect of modification has been validated by the available simulation data, except for low density system. When extended to confined real systems, the modified theoretical model also shows an encouraging prospect in description of the interfacial structure and properties.

  8. Molecular epidemiologic source tracking of orally transmitted Chagas disease, Venezuela.

    PubMed

    Segovia, Maikell; Carrasco, Hernán J; Martínez, Clara E; Messenger, Louisa A; Nessi, Anaibeth; Londoño, Juan C; Espinosa, Raul; Martínez, Cinda; Alfredo, Mijares; Bonfante-Cabarcas, Rafael; Lewis, Michael D; de Noya, Belkisyolé A; Miles, Michael A; Llewellyn, Martin S

    2013-07-01

    Oral outbreaks of Chagas disease are increasingly reported in Latin America. The transitory presence of Trypanosoma cruzi parasites within contaminated foods, and the rapid consumption of those foods, precludes precise identification of outbreak origin. We report source attribution for 2 peri-urban oral outbreaks of Chagas disease in Venezuela via high resolution microsatellite typing.

  9. Molecular Epidemiologic Source Tracking of Orally Transmitted Chagas Disease, Venezuela

    PubMed Central

    Segovia, Maikell; Martínez, Clara E.; Messenger, Louisa A.; Nessi, Anaibeth; Londoño, Juan C.; Espinosa, Raul; Martínez, Cinda; Alfredo, Mijares; Bonfante-Cabarcas, Rafael; Lewis, Michael D.; de Noya, Belkisyolé A.; Miles, Michael A.; Llewellyn, Martin S.

    2013-01-01

    Oral outbreaks of Chagas disease are increasingly reported in Latin America. The transitory presence of Trypanosoma cruzi parasites within contaminated foods, and the rapid consumption of those foods, precludes precise identification of outbreak origin. We report source attribution for 2 peri-urban oral outbreaks of Chagas disease in Venezuela via high resolution microsatellite typing. PMID:23768982

  10. Resultant vertical prism in toric soft contact lenses.

    PubMed

    Sulley, Anna; Hawke, Ryan; Lorenz, Kathrine Osborn; Toubouti, Youssef; Olivares, Giovanna

    2015-08-01

    Rotational stability of toric soft contact lenses (TSCLs) is achieved using a range of designs. Designs utilising prism or peripheral ballast may result in residual prism in the optic zone. This study quantifies the vertical prism in the central 6mm present in TSCLs with various stabilisation methods. Vertical prism was computed using published refractive index and vertical thickness changes in the central optic zone on a full lens thickness map. Thickness maps were measured using scanning transmission microscopy. Designs tested were reusable, silicone hydrogel and hydrogel TSCLs: SofLens(®) Toric, PureVision(®)2 for Astigmatism, PureVision(®) Toric, Biofinity(®) Toric, Avaira(®) Toric, clariti(®) toric, AIR OPTIX(®) for ASTIGMATISM and ACUVUE OASYS(®) for ASTIGMATISM; with eight parameter combinations for each lens (-6.00DS to +3.00DS, -1.25DC, 90° and 180° axes). All TSCL designs evaluated had vertical prism in the optic zone except one which had virtually none (0.01Δ). Mean prism ranged from 0.52Δ to 1.15Δ, with three designs having prism that varied with sphere power. Vertical prism in ACUVUE OASYS(®) for ASTIGMATISM was significantly lower than all other TSCLs tested. TSCL designs utilising prism-ballast and peri-ballast for stabilisation have vertical prism in the central optic zone. In monocular astigmats fitted with a TSCL or those wearing a mix of toric designs, vertical prism imbalance could create or exacerbate disturbances in binocular vision function. Practitioners should be aware of this potential effect when selecting which TSCL designs to prescribe, particularly for monocular astigmats with pre-existing binocular vision anomalies, and when managing complaints of asthenopia in monocular astigmats. Copyright © 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  11. Infrared hyperspectral imaging polarimeter using birefringent prisms.

    PubMed

    Craven-Jones, Julia; Kudenov, Michael W; Stapelbroek, Maryn G; Dereniak, Eustace L

    2011-03-10

    A compact short-wavelength and middle-wavelength infrared hyperspectral imaging polarimeter (IHIP) is introduced. The sensor includes a pair of sapphire Wollaston prisms and several high-order retarders to form an imaging Fourier transform spectropolarimeter. The Wollaston prisms serve as a birefringent interferometer with reduced sensitivity to vibration versus an unequal path interferometer, such as a Michelson. Polarimetric data are acquired through the use of channeled spectropolarimetry to modulate the spectrum with the Stokes parameter information. The collected interferogram is Fourier filtered and reconstructed to recover the spatially and spectrally varying Stokes vector data across the image. The IHIP operates over a ±5° field of view and implements a dual-scan false signature reduction technique to suppress polarimetric aliasing artifacts. In this paper, the optical layout and operation of the IHIP sensor are presented in addition to the radiometric, spectral, and polarimetric calibration techniques used with the system. Spectral and spectropolarimetric results from the laboratory and outdoor tests with the instrument are also presented.

  12. Portable Remote Imaging Spectrometer (PRISM): Laboratory and Field Calibration Results

    NASA Astrophysics Data System (ADS)

    Mccubbin, I. B.; Green, R. O.; Mouroulis, P.; Van Gorp, B.; Dierssen, H. M.

    2012-12-01

    The Portable Remote Imaging Spectrometer (PRISM) is an airborne sensor tailored specifically for the challenges of coastal ocean research. PRISM has high throughput, high-uniformity and low polarization sensitivity. PRISM is an airborne imaging spectrometer sensor that has been developed by the Jet Propulsion Laboratory (JPL) with funding from NASA's Earth Science and Technology Office, Airborne Science Office, and Ocean Biology and Biogeochemistry Office. Development of PRISM started in August 2009. Laboratory measurements of the sensor characteristics as well as measurements over land and water calibration sites will be reported. The objective of the PRISM program is to provide a facility instrument for the community of coastal ocean scientists in order to address specific science questions that have been identified by NASA as critical to the understanding of terrestrial processes. PRISM is a push-broom sensor, and utilizes a Dyson spectrometer, which has 3-nm spectral resolution from 350-1000 nm. The objective of the PRISM 2012 airborne campaign was to a) provide instrument calibration data by overflying specific well-characterized ground targets, and b) perform an investigation into the health of specific seagrass types as indicative of coastal habitat health in the Elkhorn Slough region of Monterey Bay, CA. In May and July of 2012 PRISM flew engineering test flights and an initial science campaign. The initial results from the May and July 2012 flight campaigns will be presented.

  13. Priorities in School Mathematics: Executive Summary of the PRISM Project.

    ERIC Educational Resources Information Center

    National Council of Teachers of Mathematics, Inc., Reston, VA.

    The Priorities in School Mathematics Project (PRISM) was designed by the National Council of Teachers of Mathematics to collect information on current beliefs and reactions to possible mathematics curriculum changes during the 1980's. The first component of PRISM was a survey of preferences for alternative content topics, instructional goals,…

  14. New Light on a Prism: The Concert for All Reasons

    ERIC Educational Resources Information Center

    Linaberry, Robin

    2004-01-01

    The prism concert concept was introduced in this country at the Eastman School of Music in 1975. The development of Eastman's inaugural prism concert is commonly attributed to Donald Hunsberger and Gustav Meier, conductors of the wind ensemble and orchestra, respectively. The basic idea is that different styles of music performed by different…

  15. Cardiac arrhythmias in Chagas' heart disease.

    PubMed

    Elizari, M V; Chiale, P A

    1993-10-01

    Chagas' disease is a chronic parasitosis affecting most Latin American countries. Its most important clinical manifestation is a late developing chronic myocarditis and, much less frequently, an early acute myocarditis. Chagasic myocardial damage is microfocal and disseminated throughout the heart. In most cases, the coexistence of areas of myocytic degeneration, inflammatory infiltration, and fibrosis suggests a permanent evolving process. Commonly, chronic chagasic myocarditis resembles a dilated cardiomyopathy, with characteristic ECG abnormalities (atrial and ventricular extrasystoles, intraventricular and/or AV conduction disturbances, and primary ST-T wave changes). Since myocardial damage is scattered throughout the heart, the ECG abnormalities (arrhythmias, conduction disturbances, and repolarization changes) are also representative of the widespread cardiac involvement. Thus, sick sinus syndrome, atrial extrasystoles, intraatrial conduction disturbances, and atrial fibrillation or flutter are common findings in different stages of the disease. At the ventricular level, both conduction disturbances and arrhythmias are conspicuous expressions of the myocardial damage. Right bundle branch block alone or in combination with left anterior hemiblock are the most common conduction defects. Further compromise of the conduction system can lead to different degrees of AV block. Chagas' disease is the main cause of bundle branch block and AV block in endemic areas. In advanced cases of Chagas' heart disease, ventricular premature contractions are extremely frequent, multiform, and repetitive (couplets and runs of ventricular tachycardia), and show R on T phenomenon. These arrhythmias are usually aggravated by increased sympathetic tone, implying an enhanced risk of cardiac sudden death among chagasic patients, which is sometimes the first manifestation of the illness. Chronic chagasic myocarditis is the leading cause of cardiovascular death, mostly as a consequence

  16. Neutral density filters with Risley prisms: analysis and design.

    PubMed

    Duma, Virgil-Florin; Nicolov, Mirela

    2009-05-10

    We achieve the analysis and design of optical attenuators with double-prism neutral density filters. A comparative study is performed on three possible device configurations; only two are presented in the literature but without their design calculus. The characteristic parameters of this optical attenuator with Risley translating prisms for each of the three setups are defined and their analytical expressions are derived: adjustment scale (attenuation range) and interval, minimum transmission coefficient and sensitivity. The setups are compared to select the optimal device, and, from this study, the best solution for double-prism neutral density filters, both from a mechanical and an optical point of view, is determined with two identical, symmetrically movable, no mechanical contact prisms. The design calculus of this optimal device is developed in essential steps. The parameters of the prisms, particularly their angles, are studied to improve the design, and we demonstrate the maximum attenuation range that this type of attenuator can provide.

  17. Large-aperture Dove prism for a rotational shearing interferometer

    NASA Astrophysics Data System (ADS)

    Moreno, Ivan; Paez, Gonzalo; Garcia-Marquez, Jorge; Strojnik, Marija

    2002-12-01

    An analytical expression is derived for the tilt introduced into a wave front by a Dove prism with manufacturing errors: error in the base angles and in the pyramidal angle. We found that the tilt decreases when the base angles are increased above the values of traditional design. The increase in the length-aperture ratio of a prism is detrimental to its performance. However, a Dove prism with a widened aperture increases throughput and keeps prism weight manageable for implementation in the rotational shearing interferometer. Thus, we propose a Dove prism designed with a widened aperture to increase throughput in the rotational shearing interferometer and with larger base angles to minimize the wave-front tilt introduced due to manufacturing errors.

  18. Modified formula of Malus’ law for Glan Taylor polarizing prisms

    NASA Astrophysics Data System (ADS)

    Zhu, Huafeng; Song, Lianke; Chen, Jianwen; Gao, Hongyi; Li, Ruxin; Xu, Zhizhan

    2005-01-01

    A simple three-axis model has been developed, which has been successfully applied to the analysis of the light transmittance in spatial incident angle and the simulation of modified formula of Malus' law for Glan-Taylor prisms. Our results indicate that the fluctuations on the cosine squared curve are due to specific misalignments between the axis of the optical system, the optical axis of the prism and the mechanical axis (rotation axis) of prism, which results in the fact that different initial relative location of the to-be-measured-prism in the testing system corresponds to different shape of Malus' law curve. Methods to get absolutely smooth curve are proposed. This analysis is available for other kinds of Glan-type prisms.

  19. Dissociating perceptual and motor effects of prism adaptation in neglect.

    PubMed

    Striemer, Christopher L; Danckert, James

    2010-04-21

    Prism adaptation reduces some symptoms of neglect; however the mechanisms underlying such changes are poorly understood. We suggest that prisms influence neglect by acting on dorsal stream circuits subserving visuomotor control, with little influence on perceptual aspects of neglect. We examined prism adaptation in three neglect patients and a group of healthy controls on line bisection and landmark tasks. Neglect patients showed a dramatic reduction in the rightward bias for line bisection, but absolutely no change in their leftward bias on the landmark task, which is a perceptual equivalent to bisection. However, in controls, prisms produced 'neglect-like' deficits on both the line bisection and landmark tasks. These data suggest that prisms influence visually guided actions more so than perception in neglect.

  20. The controversy on the early history of Chagas disease.

    PubMed

    Löwy, I

    2005-12-01

    Recently historians of medicine have proposed three distinctive accounts of early history of Chagas disease (American trypasonomiasis). According to the first the disease, described by the Brazilian researcher Carlos Chagas in 1909, was "deconstructed" in the 1920s and disappeared for about twenty years, then was recovered in the 1940s, mainly through the epidemiological studies of Emmanuel Dias and his colleagues in Minas Gerais (Brazil). According to the second Chagas disease could not be "deconstructed" in the 1920s because it did not exist at that time. Chagas observations were inaccurate and unreliable and did not define a new human pathology. The entity called today "Chagas disease" appeared in the 1930, principally as the result of investigations of Cecilio Romaña in Argentina. Finally, a third view assumes that "Chagas disease" was constructed gradually between 1909 and the 1950s through the collective efforts of numerous Latino-American researchers. This paper juxtaposes different histories of Chagas disease, and argues that their divergences stems from allegiance to distinct, partly incommensurable epistemological "thought styles". The co-existence of divergent styles of historical investigation, this text proposes, should be perceived as potential source of enrichment of our understanding of the past.

  1. Chagas disease, a risk factor for high blood pressure.

    PubMed

    Vicco, Miguel Hernán; Rodeles, Luz; Yódice, Agustina; Marcipar, Iván

    2014-12-01

    Chagas disease is a parasite infection caused by the protozoan Trypanosoma cruzi. Its most common complications is chronic Chagas heart disease but impairments of the systemic vasculature also has been observed. Although the different mechanisms that regulate blood pressure are disrupted, to our knowledge data on the association of hypertension and chronic Chagas disease are scarce. In this regard we evaluate whether Chagas disease constitutes a high blood pressure risk factor. We recruited 200 individuals, half of them with positive serology for T. cruzi. They were subjected to a complete clinical examination. The mean age of sampled individuals was 46.7 ± 12.3, and the mean of systolic and diastolic blood pressure were 124 ± 12 mmHg and 82 ± 10 mmHg, respectively. There were no between-group differences regarding age, sex distribution or body mass index. Chagas disease contributed significantly to high blood pressure (OR = 4, 95% CI 1.8323-7.0864, p = 0.0002). Our results reveal an important association between Chagas disease and high blood pressure, which should be contemplated by physicians in order to promote preventive cardiovascular actions in patients with Chagas disease.

  2. A global systematic review of Chagas disease prevalence among migrants.

    PubMed

    Conners, Erin E; Vinetz, Joseph M; Weeks, John R; Brouwer, Kimberly C

    2016-04-01

    Human migration has been identified as a potential factor for increased Chagas disease risk and has transformed the disease from a Latin American problem to a global one. We conducted a systematic review of the scientific literature between 2004-2014 in order to: summarize recent seroprevalence estimates of Chagas disease among Latin American migrants, in both endemic and non-endemic settings; compare seroprevalence estimates in migrants to countrywide prevalence estimates; and identify risk factors for Chagas disease among migrants. A total of 320 studies were screened and 23 studies were included. We found evidence that the prevalence of Chagas disease is higher than expected in some migrant groups and that reliance on blood donor screening prevalence estimates underestimates the burden of disease. Overall there is a dearth of high quality epidemiologic studies on the prevalence of Chagas disease in migrants, especially among intra-regional migrants within Latin America. Given that this zoonotic disease cannot likely be eradicated, improved surveillance and reporting is vital to continuing control efforts. More accurate health surveillance of both Latin American migrants and the Chagas disease burden will help countries appropriately scale up their response to this chronic disease. Overall, improved estimates of Chagas disease among migrants would likely serve to highlight the real need for better screening, diagnostics, and treatment of individuals living with the disease. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Dobutamine Stress Echocardiography Safety in Chagas Disease Patients

    PubMed Central

    Rassi, Daniela do Carmo; Vieira, Marcelo Luiz Campos; Furtado, Rogerio Gomes; Turco, Fabio de Paula; Melato, Luciano Henrique; Hotta, Viviane Tiemi; Nunes, Colandy Godoy de Oliveira; Rassi Jr., Luiz; Rassi, Salvador

    2017-01-01

    Background A few decades ago, patients with Chagas disease were predominantly rural workers, with a low risk profile for obstructive coronary artery disease (CAD). As urbanization has increased, they became exposed to the same risk factors for CAD of uninfected individuals. Dobutamine stress echocardiography (DSE) has proven to be an important tool in CAD diagnosis. Despite being a potentially arrhythmogenic method, it is safe for coronary patients without Chagas disease. For Chagas disease patients, however, the indication of DSE in clinical practice is uncertain, because of the arrhythmogenic potential of that heart disease. Objectives To assess DSE safety in Chagas disease patients with clinical suspicion of CAD, as well as the incidence of arrhythmias and adverse events during the exam. Methods Retrospective analysis of a database of patients referred for DSE from May/2012 to February/2015. This study assessed 205 consecutive patients with Chagas disease suspected of having CAD. All of them had their serology for Chagas disease confirmed. Results Their mean age was 64±10 years and most patients were females (65.4%). No patient had significant adverse events, such as acute myocardial infarction, ventricular fibrillation, asystole, stroke, cardiac rupture and death. Regarding arrhythmias, ventricular extrasystoles occurred in 48% of patients, and non-sustained ventricular tachycardia in 7.3%. Conclusion DSE proved to be safe in this population of Chagas disease patients, in which no potentially life-threatening outcome was found. PMID:28099588

  4. Motion control of the wedge prisms in Risley-prism-based beam steering system for precise target tracking.

    PubMed

    Zhou, Yuan; Lu, Yafei; Hei, Mo; Liu, Guangcan; Fan, Dapeng

    2013-04-20

    Two exact inverse solutions of Risley prisms have been given by previous authors, based on which we calculate the gradients of the scan field that open a way to investigate the nonlinear relationship between the slewing rate of the beam and the required angular velocities of the two wedge prisms in the Risley-prism-based beam steering system for target tracking. The limited regions and singularity point at the center and the edge of the field of regard are discussed. It is found that the maximum required rotational velocities of the two prisms for target tracking are nearly the same and are dependent on the altitude angle. The central limited region is almost independent of the prism parameters. The control singularity at the crossing center path can be avoided by switching the two solutions.

  5. Prisms and neglect: what have we learned?

    PubMed

    Newport, Roger; Schenk, Thomas

    2012-05-01

    Since Rossetti et al. (1998) reported that prism adaptation (PA) can lead to a substantial reduction of neglect symptoms PA has become a hot topic in neglect-research. More than 280 articles have been published in this area. Not all of those studies investigated the therapeutic potential of this technique, many studies examined the responsiveness to PA as a way to subdivide neglect into separate subsyndromes, other studies focussed on the process of PA itself in an effort to illuminate its underlying neurobiological mechanisms. In this article we will review research in all of these three areas to determine whether and to what extent research on PA in neglect patients has fulfilled its promise as a new way to improve the treatment of neglect, enhance our understanding of this complex syndrome and provide new insights into the neurobiology of sensorimotor learning.

  6. Prism adaptation in spinocerebellar ataxia type 2.

    PubMed

    Fernandez-Ruiz, Juan; Velásquez-Perez, Luis; Díaz, Rosalinda; Drucker-Colín, René; Pérez-González, Ruth; Canales, Nalia; Sánchez-Cruz, Gilberto; Martínez-Góngora, Edilberto; Medrano, Yaquelín; Almaguer-Mederos, Luis; Seifried, Carola; Auburger, Georg

    2007-09-20

    Patients with spinocerebellar ataxia type 2 (SCA2), develop severe pontine nuclei, inferior olives, and Purkinje cell degeneration. This form of autosomal dominant cerebellar ataxia is accompanied by progressive ataxia and dysarthria. Although the motor dysfunction is well characterized in these patients, nothing is known about their motor learning capabilities. Here we tested 43 SCA2 patients and their matched controls in prism adaptation, a kind of visuomotor learning task. Our results show that their pattern of brain damage does not entirely disrupt motor learning. Rather, patients had impaired adaptation decrement, but surprisingly a normal aftereffect. Moreover, the mutation degree could discriminate the degree of adaptation. This pattern could reflect the net contribution of two adaptive mechanisms: strategic control and spatial realignment. Accordingly, SCA2 patients show an impaired strategic control that affects the adaptation rate, but a normal spatial realignment measured through the aftereffect. Our results suggest that the neural areas subserving spatial realignment are spared in this form of spinocerebellar ataxia.

  7. Large beam deflection using cascaded prism array

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Chih; Tsui, Chi-Leung

    2012-04-01

    Endoscopes have been utilize in the medical field to observe the internals of the human body to assist the diagnosis of diseases, such as breathing disorders, internal bleeding, stomach ulcers, and urinary tract infections. Endoscopy is also utilized in the procedure of biopsy for the diagnosis of cancer. Conventional endoscopes suffer from the compromise between overall size and image quality due to the required size of the sensor for acceptable image quality. To overcome the size constraint while maintaining the capture image quality, we propose an electro-optic beam steering device based on thermal-plastic polymer, which has a small foot-print (~5mmx5mm), and can be easily fabricated using conventional hot-embossing and micro-fabrication techniques. The proposed device can be implemented as an imaging device inside endoscopes to allow reduction in the overall system size. In our previous work, a single prism design has been used to amplify the deflection generated by the index change of the thermal-plastic polymer when a voltage is applied; it yields a result of 5.6° deflection. To further amplify the deflection, a new design utilizing a cascading three-prism array has been implemented and a deflection angle to 29.2° is observed. The new design amplifies the beam deflection, while keeping the advantage of simple fabrication made possible by thermal-plastic polymer. Also, a photo-resist based collimator lens array has been added to reduce and provide collimation of the beam for high quality imaging purposes. The collimator is able to collimate the exiting beam at 4 μm diameter for up to 25mm, which potentially allows high resolution image capturing.

  8. Mechanisms underlying neglect recovery after prism adaptation.

    PubMed

    Serino, Andrea; Angeli, Valentina; Frassinetti, Francesca; Làdavas, Elisabetta

    2006-01-01

    Prism adaptation (PA) has been demonstrated to be effective in improving hemispatial neglect. However not all patients seem to benefit from this procedure. Thus, the objective of the present work is to provide behavioural and neuroanatomical predictors of recovery by exploring the reorganization of low-order visuo-motor behaviour and high-order visuo-spatial representation induced by PA. To this end, 16 neglect patients (experimental group) were submitted to a PA treatment for 10 daily sessions. Neglect and oculo-motor responses were assessed before the treatment, 1 week, 1 and 3 months after the treatment. Eight control patients, who received general cognitive stimulation, were submitted to the same tests at the same time interval. The results showed that experimental patients obtained, as a consequence of PA, a long lasting neglect recovery, a reorganization of low-order visuo-motor behaviour during and after prism exposure (error reduction and after-effect, respectively) and a leftward deviation of oculo-motor responses. Importantly, the level of error reduction obtained in the first week of treatment was predictive of neglect recovery and the amelioration of oculo-motor responses, and the degree of eye movement deviation was positively related to neglect amelioration. Finally, the study of patients' neuroanatomical data showed that severe occipital lesions were associated with a lack of error reduction, poor neglect recovery and reduced oculo-motor system amelioration. In conclusion, the present results suggest that low-order visuo-motor reorganization induced by PA promotes a resetting of the oculo-motor system leading to an improvement in high-order visuo-spatial representation able to ameliorate neglect.

  9. Immunoregulatory networks in human Chagas disease

    PubMed Central

    Dutra, Walderez O.; Menezes, Cristiane A.S.; Magalhães, Luisa M. D.; Gollob, Kenneth J.

    2014-01-01

    Summary Chagas disease, caused by the infection with Trypanosoma cruzi, is endemic in all Latin America. Due to the increase in population migration, Chagas disease has spread worldwide and is now considered a health issue not only in endemic countries. While most chronically infected individuals remain asymptomatic, approximately 30% of the patients develop a potentially deadly cardiomyopathy. The exact mechanisms that underlie the establishment and maintenance of the cardiac pathology are not clear. However, there is consistent evidence that immunoregulatory cytokines are critical for orchestrating the immune response and, thus, influence disease development or control. While the asymptomatic (indeterminate) form represents a state of balance between the host and the parasite, the establishment of the cardiac form represents the loss of this balance. Analysis of data obtained from several studies have led to the hypothesis that the indeterminate form is associated with an anti-inflammatory cytokine profile, represented by high expression of IL-10, while cardiac form is associated with a high production of IFN-gamma and TNF-alpha in relation to IL-10, leading to an inflammatory profile. Here, we discuss the immunoregulatory events that might influence disease outcome, as well as the mechanisms that influence the establishment of these complex immunoregulatory networks. PMID:24611805

  10. [Part V. Laboratory diagnosis of Chagas disease].

    PubMed

    Apt B, Werner; Heitmann G, Ingrid; Jercic L, M Isabel; Jofré M, Leonor; Muñoz C Del V, Patricia; Noemí H, Isabel; San Martín V, Ana M; Sapunar P, Jorge; Torres H, Marisa; Zulantay A, Inés

    2008-10-01

    In this fifth part of Guidelines for Chagas disease, diagnostic techniques for Trypanosoma cruzi infection in humans are reviewed, the interpretation of laboratory results and an algorithm for laboratory diagnosis in immunocompetent hosts are presented. Chagas disease may be diagnosed by three kinds of techniques: direct, which allow detect the presence of the parasite in different kind of samples; indirect, based on the search of immune specific response against T. cruzi antigens and molecular, which detect parasite genetic material. Direct techniques are utilized mainly in acute phase of disease, as the parasite is present in blood of infected host. These techniques do not require be confirmed by other methods. For chronic undetermined phase and for symptomatic phase it is recommended to use indirect techniques; generally, immunoassay techniques (ELISA) that detect IgG antibodies directed against T. cruzi antigens are performed. As false positive results are possible, a positive or undetermined result must be confirmed by at least another technique (indirect immunofluorescence or indirect hemmaglutination). In Chile, confirmation of infection is performed by the Instituto de Salud Pública National Reference Laboratory or at surrogate centers. Molecular methods may be used to make the diagnosis in acute or chronic phase of infection, with more accuracy in the acute phase, and it is mainly recommended to diagnose vertical transmission of T. cruzi as early diagnosis of congenital infection increases the possibility to cure the sibling and besides it is a good marker to evaluate the effectiveness of treatment.

  11. Chagas disease and globalization of the Amazon.

    PubMed

    Briceño-León, Roberto

    2007-01-01

    The increasing number of autochthonous cases of Chagas disease in the Amazon since the 1970s has led to fear that the disease may become a new public health problem in the region. This transformation in the disease's epidemiological pattern in the Amazon can be explained by environmental and social changes in the last 30 years. The current article draws on the sociological theory of perverse effects to explain these changes as the unwanted result of the shift from the "inward" development model prevailing until the 1970s to the "outward" model that we know as globalization, oriented by industrial forces and international trade. The current article highlights the implementation of five new patterns in agriculture, cattle-raising, mining, lumbering, and urban occupation that have generated changes in the environment and the traditional indigenous habitat and have led to migratory flows, deforestation, sedentary living, the presence of domestic animals, and changes in the habitat that facilitate colonization of human dwellings by vectors and the domestic and work-related transmission of the disease. The expansion of Chagas disease is thus a perverse effect of the globalization process in the Amazon.

  12. Chagas' Disease: Pregnancy and Congenital Transmission

    PubMed Central

    Hernández, Roberto

    2014-01-01

    Chagas disease is a chronic infection that kills approximately 12,000 people a year. Mass migration of chronically infected and asymptomatic persons has caused globalization of Chagas disease and has made nonvectorial infection, including vertical and blood-borne transmission, more of a threat to human communities than vectorial infection. To control transmission, it is essential to test all pregnant women living in endemic countries and all pregnant women having migrated from, or having lived in, endemic countries. All children born to seropositive mothers should be tested not only within the first month of life but also at ~6 months and ~12 months of age. The diagnosis is made by identification of the parasite in blood before the age of 6 months and by identification of the parasite in blood and/or positive serology after 10 months of age. Follow up for a year is essential as a significant proportion of cases are initially negative and are only detected at a later stage. If the condition is diagnosed and treated early, the clinical response is excellent and the majority of cases are cured. PMID:24949443

  13. Chagas disease: changes in knowledge and management.

    PubMed

    Lescure, François-Xavier; Le Loup, Guillaume; Freilij, Hector; Develoux, Michel; Paris, Luc; Brutus, Laurent; Pialoux, Gilles

    2010-08-01

    More than 100 years after the discovery of human American trypanosomiasis by Carlos Chagas, our knowledge and management of the disease are profoundly changing. Substantial progress made by disease control programmes in most endemic areas contrasts with persisting difficulties in the Gran Chaco region in South America and the recent emergence of the disease in non-endemic areas because of population movements. In terms of pathogenesis, major discoveries have been made about the life cycle and genomics of Trypanosoma cruzi, and the role of the parasite itself in the chronic phase of the disease. From a clinical perspective, a growing number of arguments have challenged the notion of an indeterminate phase, and suggest new approaches to manage patients. New methods such as standardised PCR will be necessary to ensure follow-up of this chronic infection. Although drugs for treatment of Chagas disease are limited, poorly tolerated, and not very effective, treatment indications are expanding. The results of the Benznidazole Evaluation For Interrupting Trypanosomiasis (BENEFIT) trial in 2012 will also help to inform treatment. Mobilisation of financial resources to fund research on diagnosis and randomised controlled trials of treatment are international health priorities.

  14. Melatonin in Chagas' disease. Possible therapeutic value.

    PubMed

    Cardinali, Daniel P; Alvarez, Carlos B

    2011-01-01

    Chagas' disease is a severe health problem in Latin America, causing approximately 50 000 deaths a year, with approximately 18 million infected people. About 25-30% of the patients infected with Trypanosoma cruzi develop the chronic form of the disease. The protective response against T. cruzi depends on both innate and acquired immunity involving macrophages, natural killer cells, T and B lymphocytes, and the production of proinflammatory Th-1 cytokines. In addition, an increased nitric oxide (NO) production in macrophages leading to effective microbicidal action is needed to control parasitemia. Melatonin is detectable in T. cruzi and may play a role in promoting infection whereas, when administered in high doses during the acute phase of T. cruzi infection, it can decrease parasitemia while reducing NO production. During chronic disease progression, the sustained oxidative stress concomitant to myocardial damage could be reduced by administering melatonin. It is hypothesized that the coordinated administration of a melatonin agonist like the MT1 /MT2 agonist ramelteon, that lacks antioxidant activity and may not affect NO production during the acute phase, and of melatonin in doses high enough to decrease oxidative damage, to preserve mitochondrial and to prevent cardiomyopathy during the chronic phase, could be a novel add-on treatment of Chagas' disease.

  15. Current and Future Chemotherapy for Chagas Disease.

    PubMed

    Gaspar, Luís; Moraes, Carolina B; Freitas-Junior, Lucio H; Ferrari, Stefania; Costantino, Luca; Costi, Maria Paola; Coron, Ross P; Smith, Terry K; Siqueira-Neto, Jair L; McKerrow, James H; Cordeiro-da-Silva, Anabela

    2015-01-01

    Human American trypanosomiasis, commonly called Chagas disease, is one of the most neglected illnesses in the world and remains one of the most prevalent chronic infectious diseases of Latin America with thousands of new cases every year. The only treatments available have been introduced five decades ago. They have serious, undesirable side effects and disputed benefits in the chronic stage of the disease - a characteristic and debilitating cardiomyopathy and/or megavisceras. Several laboratories have therefore focused their efforts in finding better drugs. Although recent years have brought new clinical trials, these are few and lack diversity in terms of drug mechanism of action, thus resulting in a weak drug discovery pipeline. This fragility has been recently exposed by the failure of two candidates; posaconazole and E1224, to sterilely cure patients in phase 2 clinical trials. Such setbacks highlight the need for continuous, novel and high quality drug discovery and development efforts to discover better and safer treatments. In this article we will review past and current findings on drug discovery for Trypanosoma cruzi made by academic research groups, industry and other research organizations over the last half century. We also analyze the current research landscape that is now better placed than ever to deliver alternative treatments for Chagas disease in the near future.

  16. [The third and new face of Chagas disease].

    PubMed

    Pays, J-F

    2016-08-01

    After the publication of the results of the BENEFIT study concluding that the benznidazole (5 mg/kg/d/60 d) is ineffective to stop the progression of the established Chagas' cardiomyopathy in adults, the author evokes the new experiences and the new challenges of 2016 regarding Chagas disease while speculating on its future and by calling back some elements little known of his history, in particular the fact that it is Chagas who invented about it to some extent the concept of "neglected disease".

  17. Goldmann Tonometer Prism with an Optimized Error Correcting Applanation Surface

    PubMed Central

    McCafferty, Sean; Lim, Garrett; Duncan, William; Enikov, Eniko; Schwiegerling, Jim

    2016-01-01

    Purpose We evaluate solutions for an applanating surface modification to the Goldmann tonometer prism, which substantially negates the errors due to patient variability in biomechanics. Methods A modified Goldmann or correcting applanation tonometry surface (CATS) prism is presented which was optimized to minimize the intraocular pressure (IOP) error due to corneal thickness, stiffness, curvature, and tear film. Mathematical modeling with finite element analysis (FEA) and manometric IOP referenced cadaver eyes were used to optimize and validate the design. Results Mathematical modeling of the optimized CATS prism indicates an approximate 50% reduction in each of the corneal biomechanical and tear film errors. Manometric IOP referenced pressure in cadaveric eyes demonstrates substantial equivalence to GAT in nominal eyes with the CATS prism as predicted by modeling theory. Conclusion A CATS modified Goldmann prism is theoretically able to significantly improve the accuracy of IOP measurement without changing Goldmann measurement technique or interpretation. Clinical validation is needed but the analysis indicates a reduction in CCT error alone to less than ±2 mm Hg using the CATS prism in 100% of a standard population compared to only 54% less than ±2 mm Hg error with the present Goldmann prism. Translational Relevance This article presents an easily adopted novel approach and critical design parameters to improve the accuracy of a Goldmann applanating tonometer. PMID:27642540

  18. Pure rotation of a prism on a ramp

    PubMed Central

    Zhao, Zhen; Liu, Caishan; Ma, Daolin

    2014-01-01

    In this work, we study a prism with a cross section in polygon rolling on a ramp inclined at a small angle. The prism under gravity rolls purely around each individual edge, intermittently interrupted by a sequence of face collisions between the side face of the prism and the ramp. By limiting the prism in a planar motion, we propose a mathematical model to deal with the events of the impacts. With a pair of laser-Doppler vibrometers, experiments are also conducted to measure the motions of various prisms made of different materials and with different edge number. Not only are good agreements achieved between our numerical and experimental results, but also an intriguing physical phenomenon is discovered: the purely rolling motion is nearly independent of the prism's materials, yet it is closely related to the prism's geometry. Imagine that an ideal circular section can be approximately equivalent to a polygon with a large enough edge number N, the finding presented in this paper may help discover the physical mechanism of rolling friction. PMID:25197242

  19. Suicidality assessment with PRISM-S - simple, fast, and visual: a brief nonverbal method to assess suicidality in adolescent and adult patients.

    PubMed

    Harbauer, Gregor; Ring, Mariann; Schuetz, Christopher; Andreae, Andreas; Haas, Sebastian

    2013-01-01

    The PRISM-S task was developed at the Crisis Intervention Center (KIZ) Winterthur, Switzerland, to enable an assessment of the degree of suicidality in less than 5 minutes with a simple, visual instrument. Comparison of validity and clinical use of the new PRISM-S task with other instruments known as "gold standards". Quantitative pilot study enlisting 100 inpatients admitted to the KIZ, aged 15-42 years. Patients' suicidality was assessed by the PRISM-S task during the first clinical interview and compared to data obtained by standardized suicidality instruments. The patients completed the PRISM-S task in 2 to 5 minutes without difficulty. Data show significant positive correlations between the suicidality as assessed by PRISM-S and the gold standards, i.e., DSI-SS (r = 0.59, N = 65, p < .0001). There is no strong evidence that PRISM-S is useful for outpatients or in other settings. The experiences gained with outpatients/patients with other disorders are promising but have not been systematically evaluated. The results do not rely on a randomized design. The sample consists of persons coming to the crisis intervention center. PRISM-S offers a brief, easy-to-administer, and valid method to assess patients' suicidality. The simple instruction facilitates its use in other languages and other cultures as well. The acceptance by patients and health professionals was good, with no one refusing to complete the task.

  20. Peripheral Prism Glasses: Effects of Dominance, Suppression and Background

    PubMed Central

    Ross, Nicole C.; Bowers, Alex R.; Optom, M.C.; Peli, Eli

    2012-01-01

    Purpose Unilateral peripheral prisms for homonymous hemianopia (HH) place different images on corresponding peripheral retinal points, a rivalrous situation in which local suppression of the prism image could occur and thus limit device functionality. Detection with peripheral prisms has primarily been evaluated using conventional perimetry where binocular rivalry is unlikely to occur. We quantified detection over more visually complex backgrounds and examined the effects of ocular dominance. Methods Detection rates of 8 participants with HH or quadranopia and normal binocularity wearing unilateral peripheral prism glasses were determined for static perimetry targets briefly presented in the prism expansion area (in the blind hemifield) and the seeing hemifield, under monocular and binocular viewing, over uniform gray and more complex patterned backgrounds. Results Participants with normal binocularity had mixed sensory ocular dominance, demonstrated no difference in detection rates when prisms were fitted on the side of the HH or the opposite side (p>0.2), and had detection rates in the expansion area that were not different for monocular and binocular viewing over both backgrounds (p>0.4). However, two participants with abnormal binocularity and strong ocular dominance demonstrated reduced detection in the expansion area when prisms were fitted in front of the non-dominant eye. Conclusions We found little evidence of local suppression of the peripheral prism image for HH patients with normal binocularity. However, in cases of strong ocular dominance, consideration should be given to fitting prisms before the dominant eye. Although these results are promising, further testing in more realistic conditions including image motion is needed. PMID:22885783

  1. Prism adaptation does not alter configural processing of faces

    PubMed Central

    Bultitude, Janet H.; Downing, Paul E.; Rafal, Robert D.

    2013-01-01

    Patients with hemispatial neglect (‘neglect’) following a brain lesion show difficulty responding or orienting to objects and events on the left side of space. Substantial evidence supports the use of a sensorimotor training technique called prism adaptation as a treatment for neglect. Reaching for visual targets viewed through prismatic lenses that induce a rightward shift in the visual image results in a leftward recalibration of reaching movements that is accompanied by a reduction of symptoms in patients with neglect. The understanding of prism adaptation has also been advanced through studies of healthy participants, in whom adaptation to leftward prismatic shifts results in temporary neglect-like performance. Interestingly, prism adaptation can also alter aspects of non-lateralised spatial attention. We previously demonstrated that prism adaptation alters the extent to which neglect patients and healthy participants process local features versus global configurations of visual stimuli. Since deficits in non-lateralised spatial attention are thought to contribute to the severity of neglect symptoms, it is possible that the effect of prism adaptation on these deficits contributes to its efficacy. This study examines the pervasiveness of the effects of prism adaptation on perception by examining the effect of prism adaptation on configural face processing using a composite face task. The composite face task is a persuasive demonstration of the automatic global-level processing of faces: the top and bottom halves of two familiar faces form a seemingly new, unknown face when viewed together. Participants identified the top or bottom halves of composite faces before and after prism adaptation. Sensorimotor adaptation was confirmed by significant pointing aftereffect, however there was no significant change in the extent to which the irrelevant face half interfered with processing. The results support the proposal that the therapeutic effects of prism adaptation

  2. Performance characterization of scanning beam steered by tilting double prisms.

    PubMed

    Li, Anhu; Yi, Wanli; Zuo, Qiyou; Sun, Wansong

    2016-10-03

    A pair of orthogonal tilting double prisms with a tracking precision better than submicroradian order exhibits a good application potential in laser tracking fields. In the paper, the beam scanning performance determined by both the structure parameters and the tilting motions of two prisms is overall investigated. The functional relation between the structure parameters and the exact beam scanning range is established, the capability of high-accuracy beam steering is validated together with the investigation of the scanning error sources and the nonlinear control laws, and the beam shape distortion degree under multi-parameter combinations is demonstrated. These studies can provide important references for the development of tilting double prisms.

  3. Error compensation in a pointing system based on Risley prisms.

    PubMed

    Bravo-Medina, Beethoven; Strojnik, Marija; Garcia-Torales, Guillermo; Torres-Ortega, Hector; Estrada-Marmolejo, Ruben; Beltrán-González, Anuar; Flores, Jorge L

    2017-03-10

    Risley prisms are widely used for beam pointing in several optical systems. The exact solution for the inverse problem does not exist, except using numerical methods. However, the errors introduced by misalignment are usually greater than the approximation errors. We present a novel method to compensate alignment errors in pointing systems based on Risley prisms. The prism model that we used is based on paraxial approximation with an additional vector to compensate typical alignment errors. Simulation and experimental results show that the improvement in pointing accuracy is achievable even in comparison with exact ray tracing methods.

  4. Tonometer prism sterilisation: a local and UK national survey.

    PubMed

    Chandra, Aman; Barsam, Allon; Hammond, Christopher J

    2008-02-01

    First to audit local adherence to a protocol of use of an alcohol wipe for each tonometry, and secondly to assess current practice nationally in the UK. The audit was carried out at two units: The West Kent Eye Centre at the Princess Royal University Hospital (Orpington, UK) and Queen Mary's Hospital (Sidcup, UK). The standard set for this audit was 100% sterilisation. During a 1-week period in November 2005, the number of alcohol wipes was counted in each consultation room after outpatient clinics, with the doctors being assessed blind to the survey. The number of Goldman applanation tonometry intra-ocular pressures recorded by each clinician was counted by inspection of the medical records of patients seen. Secondly, departments listed in the UK Directory of Training Posts were contacted by telephone and the senior nurse was interviewed. They were asked directly about their department's tonometer prism sterilisation and management. The local audit showed only 54% of tonometry measurements were associated with sterilisation using an alcohol-impregnated wipe. The national survey included 140 of the 152 UK training departments. Thirty-three (23.6%) departments used disposable tonometer prisms routinely. The remaining 107 (76.4%) used non-disposable prisms. Eighty-five (60.7%) departments provided sodium hypochlorite for prism sterilisation, with 69 (81.2%) of these departments providing more than one prism/clinician to allow full exposure to the disinfectant. Twenty-two (15.7%) departments used alcohol wipes. Only 8 (7.5%) of the 107 departments using non-disposable prisms tracked these prisms, despite Royal College of Ophthalmologists guidelines that they should be. These same 8 (7.5%) departments replaced the non-disposable prisms as per manufacturer guidelines. 19.3% of charge nurses were aware of a policy for tonometry in patients with, or at risk of, prion disease. This study highlights that sterilisation of tonometer prisms was inconsistent in a local audit

  5. American Trypanosomiasis (Also Known as Chagas Disease) Detailed FAQs

    MedlinePlus

    ... Trypanosoma cruzi , which is transmitted to animals and people by insect vectors that are found only in the Americas (mainly, in rural areas of Latin America where poverty is widespread). Chagas disease ( T. cruzi infection) is ...

  6. 2 nd Brazilian Consensus on Chagas Disease, 2015.

    PubMed

    Dias, João Carlos Pinto; Ramos, Alberto Novaes; Gontijo, Eliane Dias; Luquetti, Alejandro; Shikanai-Yasuda, Maria Aparecida; Coura, José Rodrigues; Torres, Rosália Morais; Melo, José Renan da Cunha; Almeida, Eros Antonio de; Oliveira, Wilson de; Silveira, Antônio Carlos; Rezende, Joffre Marcondes de; Pinto, Fabiane Scalabrini; Ferreira, Antonio Walter; Rassi, Anis; Fragata, Abílio Augusto; Sousa, Andréa Silvestre de; Correia, Dalmo; Jansen, Ana Maria; Andrade, Glaucia Manzan Queiroz; Britto, Constança Felícia De Paoli de Carvalho; Pinto, Ana Yecê das Neves; Rassi, Anis; Campos, Dayse Elisabeth; Abad-Franch, Fernando; Santos, Silvana Eloi; Chiari, Egler; Hasslocher-Moreno, Alejandro Marcel; Moreira, Eliane Furtado; Marques, Divina Seila de Oliveira; Silva, Eliane Lages; Marin-Neto, José Antonio; Galvão, Lúcia Maria da Cunha; Xavier, Sergio Salles; Valente, Sebastião Aldo da Silva; Carvalho, Noêmia Barbosa; Cardoso, Alessandra Viana; Silva, Rafaella Albuquerque E; Costa, Veruska Maia da; Vivaldini, Simone Monzani; Oliveira, Suelene Mamede; Valente, Vera da Costa; Lima, Mayara Maia; Alves, Renato Vieira

    2016-12-01

    Chagas disease is a neglected chronic condition with a high burden of morbidity and mortality. It has considerable psychological, social, and economic impacts. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence. The consensus is based on the articulation and strategic contribution of renowned Brazilian experts with knowledge and experience on various aspects of the disease. It is the result of a close collaboration between the Brazilian Society of Tropical Medicine and the Ministry of Health. It is hoped that this document will strengthen the development of integrated actions against Chagas disease in the country, focusing on epidemiology, management, comprehensive care (including families and communities), communication, information, education, and research .

  7. Tc-99m pyrophosphate myocardial scanning in Chagas' disease

    SciTech Connect

    Goncalves da Rocha, A.F.; Meguerian, B.A.; Harbert, J.C.

    1981-04-01

    Chagas' disease is a serious protozoan infection affecting up to 20% of populations in some endemic areas. Myocarditis and cardiomyopathy occur in 50% of patients who go on to develop chronic Chagas's disease. We have studied a patient with no overt cardiac symptoms who revealed intense myocardial uptake of Tc-99m pyrophosphate. The significance of this finding in relation to early detection and progress of therapy is explored.

  8. Tc-99m pyrophosphate myocardial scanning in Chagas' disease

    SciTech Connect

    da Rocha, A.F.; Meguerian, B.A.; Harbert, J.C.

    1981-04-01

    Chagas' disease is a serious protozoan infection affecting up to 20% of populations in some endemic areas. Myocarditis and cardiomyopathy occur in 50% of patients who go on to develop chronic Chagas' disease. We have studied a patient with no overt cardiac symptoms who revealed intense myocardial uptake of Tc-99m pyrophosphate. The significance of this finding in relation to early detection and progress of therapy is explored.

  9. Therapeutical approaches under investigation for treatment of Chagas disease.

    PubMed

    Bahia, Maria Terezinha; Diniz, Lívia de Figueiredo; Mosqueira, Vanessa Carla Furtado

    2014-09-01

    A century after its discovery, American trypanosomiasis or Chagas disease remains a serious health problem in Latin America, where it affects around 7 - 8 million people. The prevalence of Chagas disease in the poorer parts of the world has meant that it has largely been neglected with limited progress that made in identifying new drugs for the treatment. The nitroheterocyclic drugs nifurtimox and benznidazole are first-line drugs available for Chagas disease with limitations that include variable efficacy, long treatment courses and toxicity. This review focuses on different therapeutic strategies that have been used for the discovery of new treatments for Chagas disease. These include combination chemotherapy, drug repositioning, re-dosing regimens for current drugs and the identification of new drugs with specified target profiles. There are currently several reasons for a more optimistic view about chemotherapy with Chagas disease. However, despite some progress being made in preclinical studies, there is yet to be an ideal drug or formulation for human treatment. One major drawback in the evaluation of potential Chagas disease therapeutics is the lack of tools available to perform the said evaluation. Indeed, there is a great need to discover a better biomarker that could determine the efficacy of potential chemotherapeutics in treated patients.

  10. Altered Cardiomyocyte Function and Trypanosoma cruzi Persistence in Chagas Disease.

    PubMed

    Cruz, Jader Santos; Santos-Miranda, Artur; Sales-Junior, Policarpo Ademar; Monti-Rocha, Renata; Campos, Paula Peixoto; Machado, Fabiana Simão; Roman-Campos, Danilo

    2016-05-04

    Chagas disease, caused by the triatominae Trypanosoma cruzi, is one of the leading causes of heart malfunctioning in Latin America. The cardiac phenotype is observed in 20-30% of infected people 10-40 years after their primary infection. The cardiac complications during Chagas disease range from cardiac arrhythmias to heart failure, with important involvement of the right ventricle. Interestingly, no studies have evaluated the electrical properties of right ventricle myocytes during Chagas disease and correlated them to parasite persistence. Taking advantage of a murine model of Chagas disease, we studied the histological and electrical properties of right ventricle in acute (30 days postinfection [dpi]) and chronic phases (90 dpi) of infected mice with the Colombian strain of T. cruzi and their correlation to parasite persistence. We observed an increase in collagen deposition and inflammatory infiltrate at both 30 and 90 dpi. Furthermore, using reverse transcriptase polymerase chain reaction, we detected parasites at 90 dpi in right and left ventricles. In addition, we observed action potential prolongation and reduced transient outward K(+) current and L-type Ca(2+) current at 30 and 90 dpi. Taking together, our results demonstrate that T. cruzi infection leads to important modifications in electrical properties associated with inflammatory infiltrate and parasite persistence in mice right ventricle, suggesting a causal role between inflammation, parasite persistence, and altered cardiomyocyte function in Chagas disease. Thus, arrhythmias observed in Chagas disease may be partially related to altered electrical function in right ventricle. © The American Society of Tropical Medicine and Hygiene.

  11. [Chagas disease in the Americas: an ecohealth perspective].

    PubMed

    Briceño-León, Roberto

    2009-01-01

    The historical processes involved in Chagas disease transmission relate to the patterns and conditions of human settlements, especially in rural areas, due to proximity to forest areas, where both vectors and Trypanosoma cruzi can occur, combined with precarious housing conditions and underlying poverty. However, seasonal and permanent rural-urban migration has played a major role in re-mobilizing vectors, T. cruzi, and Chagas-infected individuals. A new agricultural frontier in the Amazon has led to a new transmission pattern, especially with palm trees located close to houses. Improved blood bank surveillance has decreased transmission by blood transfusions. International migration also plays a role in Chagas disease epidemiology. The United States and Spain, where specific health services for Chagas disease diagnosis and treatment are largely absent, harbor an unknown number of individuals with Chagas, probably infected decades ago. The article discusses major strides in Chagas disease knowledge and control, besides identifying persistent gaps, such as the need for housing improvements, especially in poor rural areas in the Americas.

  12. MEGARA Optics: stain removal in PBM2Y prisms

    NASA Astrophysics Data System (ADS)

    Aguirre-Aguirre, D.; Izazaga-Pérez, R.; Villalobos-Mendoza, B.; Carrasco, E.; Gil de Paz, A.; Gallego, J.; Iglesias, J.

    2017-01-01

    MEGARA is the new integral-field and multi-object optical spectrograph for the GTC. For medium and high resolution, the dispersive elements are volume phase holographic gratings, sandwiched between two flat windows and two prisms of high optical precision. The prisms are made of Ohara PBM2Y optical glass. After the prisms polishing process, some stains appeared on the surfaces. For this, in this work is shown the comparative study of five different products (muriatic acid, paint remover, sodium hydroxide, aqua regia and rare earth liquid polish) used for trying to eliminate the stains of the HR MEGARA prisms. It was found that by polishing with the hands the affected area, and using a towel like a kind of pad, and polish during five minutes using rare earth, the stains disappear completely affecting only a 5% the rms of the surface quality. Not so the use of the other products that did not show any apparent result.

  13. Prisms with total internal reflection as solar reflectors

    DOEpatents

    Rabl, Arnulf; Rabl, Veronika

    1978-01-01

    An improved reflective wall for radiant energy collection and concentration devices is provided. The wall is comprised of a plurality of prisms whose frontal faces are adjacent and which reflect the desired radiation by total internal reflection.

  14. The infrared bands Pechan prism axis parallel detection method

    NASA Astrophysics Data System (ADS)

    Qiang, Hua; Ji, Ming; He, Yu-lan; Wang, Nan-xi; Chang, Wei-jun; Wang, Ling; Liu, Li

    2017-02-01

    In this paper, we put forward a new method to adjust the air gap of the total reflection air gap of the infrared Pechan prism. The adjustment of the air gap in the air gap of the Pechan prism directly affects the parallelism of the optical axis, so as to affect the consistency of the optical axis of the infrared system. The method solves the contradiction between the total reflection and the high transmission of the infrared wave band, and promotes the engineering of the infrared wave band. This paper puts forward the method of adjusting and controlling, which can ensure the full reflection and high penetration of the light, and also can accurately measure the optical axis of the optical axis of the different Pechan prism, and can achieve the precision of the level of the sec. For Pechan prism used in the infrared band image de rotation, make the product to realize miniaturization, lightweight plays an important significance.

  15. 5. VIEW NORTHWEST SHOWING AQUEDUCT PRISM. NOTE INTERIOR STONE WORK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW NORTHWEST SHOWING AQUEDUCT PRISM. NOTE INTERIOR STONE WORK OF THE PARAPET WALL AND REMAINS OF 1920 TIMBER AND CONCRETE FLOORING SYSTEM. - Chesapeake & Ohio Canal, Conococheague Creek Aqueduct, Milepost 99.80, Williamsport, Washington County, MD

  16. 3. ELEVATION. FROM SOUTH WITH CANAL PRISM. Canal Road ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. ELEVATION. FROM SOUTH WITH CANAL PRISM. - Canal Road Bridge, Canal Road spanning Delaware Canal Diversion, Locks 22 & 23 in Delaware Canal State Park in Williams Township, Raubsville, Northampton County, PA

  17. Development of an unbonded capping system for clay masonry prisms

    SciTech Connect

    Crouch, L.K.; Henderson, R.C.; Sneed, W.A. Jr.

    1999-07-01

    To ascertain if an unbonded capping system was feasible for clay masonry prisms, the compressive strengths of thirty clay masonry prisms capped with an unbonded capping system modeled after ASTM C 1231 were compared with those of thirty masonry prisms capped with ASTM C 67 approved high-strength gypsum cement at the ages of 7 and 28 days. All prisms were constructed by a professional mason using Grade SW, Type FBS cored face brick from the same lot and ASTM C 270 Type S PC-lime mortar. There was no significant difference in mean compressive strength for the two capping methods at either age. In addition, capping with the unbonded capping system was faster and easier. Further, 28-day results obtained using the unbonded capping system had a lower coefficient of variation and higher mean compressive strength than those obtained with high-strength gypsum.

  18. NORTHERLY STRETCH OF MILLBURY PORTION; GENERAL VIEW ACROSS CANAL PRISM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTHERLY STRETCH OF MILLBURY PORTION; GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM (LATER FILL ENCROACHING LEFT) NEAR CENTER OF THIS STRETCH; VIEW TO SOUTHWEST - Blackstone Canal Worcester-Millbury Segment, Eastern bank of Blackstone River, Millbury, Worcester County, MA

  19. PRISM: Shedding Light on NCTM's Recommendations for the 1980s.

    ERIC Educational Resources Information Center

    Suydam, Marilyn N; Higgins, Jon L.

    1980-01-01

    Information from the Priorities in School Mathematics (PRISM) project, designed as a systematic attempt to assess preferences and priorities for mathematics curriculum change, are presented in relation to eight NCTM recommendations. (MP)

  20. Strongly-Refractive One-Dimensional Photonic Crystal Prisms

    NASA Technical Reports Server (NTRS)

    Ting, David Z. (Inventor)

    2004-01-01

    One-dimensional (1D) photonic crystal prisms can separate a beam of polychromatic electromagnetic waves into constituent wavelength components and can utilize unconventional refraction properties for wavelength dispersion over significant portions of an entire photonic band rather than just near the band edges outside the photonic band gaps. Using a ID photonic crystal simplifies the design and fabrication process and allows the use of larger feature sizes. The prism geometry broadens the useful wavelength range, enables better optical transmission, and exhibits angular dependence on wavelength with reduced non-linearity. The properties of the 1 D photonic crystal prism can be tuned by varying design parameters such as incidence angle, exit surface angle, and layer widths. The ID photonic crystal prism can be fabricated in a planar process, and can be used as optical integrated circuit elements.

  1. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld and... also exempt from the current good manufacturing practice requirements of the quality system regulation...

  2. Broadband asymmetric acoustic transmission through an acoustic prism

    NASA Astrophysics Data System (ADS)

    Song, Ailing; Chen, Tianning; Wang, Xiaopeng; Xi, Yanhui

    2017-08-01

    Narrow bandwidth and complex structure are the main shortcomings of the existing asymmetric acoustic transmission devices. In this letter, a simple broadband asymmetric acoustic transmission device is proposed by using an acoustic prism filled with xenon gas. The sound pressure field distributions, the transmission spectra, and the prism angle effect are numerically investigated by using finite element method. The proposed device can always realize asymmetric acoustic transmission for the wave frequency larger than 480 Hz because the wave paths are not influenced by the wave frequencies. The asymmetric acoustic transmission is attributed to normal refraction and total reflection occur at different interfaces. Besides, relatively high transmission efficiency is realized due to the similar impedance between the acoustic prism and background. And the transmitted wave direction can be controlled freely by changing the prism angle. Our design provides a simple method to obtain broadband asymmetric acoustic transmission device and has potentials in many applications, such as noise control and medical ultrasound.

  3. Why Is White Light Dispersed by a Prism?

    ERIC Educational Resources Information Center

    Crawford, Frank S.

    1979-01-01

    Presents the answer to a question, which is intended for high school students, about the dispersion of white light by a glass prism. Why the high frequency waves travel slower than the lower frequencies in glass is also presented. (HM)

  4. Serological screening of Chagas disease in an immigrant population in Asturias, Spain proceeding from Chagas-endemic areas.

    PubMed

    Rodríguez-Guardado, Azucena; Rodríguez, Mercedes; Alonso, Paula; Seco, Carolina; Flores-Chavez, Maria; Mejuto, Patricia; Cartón, Jose A

    2009-01-01

    Population movements from Chagas disease-endemic areas to non-endemic countries due to immigration make the occurrence of this disease in these latter areas possible. We describe the results of a screening programme conducted in an immigrant population from endemic areas, attending the Tropical Medicine Unit of the Hospital Central de Asturias between June 2006 and June 2008. The ID-Chagas antibody test (particle gel immunoassay (PaGIA); DiaMed-ID) was used as a screening assay. We analysed 64 patients, 9 of whom (14%) tested positive for Chagas disease antibodies, a diagnosis that was confirmed in all cases. Six patients came from Bolivia, 2 from Paraguay and 1 from Brazil. Chagas disease is of increasing importance, even in areas with low migratory flows; hence screening programmes for this population group are especially important.

  5. Stereoscopic Display on Computer Monitor Using a Single Wedge Prism

    NASA Astrophysics Data System (ADS)

    Park, Tae-Soo; Park, Chan-Young; Lee, Han-Bae; Park, Seung-Han

    2002-02-01

    We propose a novel stereoscopic display technique which uses only a single wedge prism. It can provide good depth perception from a stereoscopic pair image displayed on a computer monitor. One element of the stereoscopic pair image is inversely distorted to correct the deformation induced by the wedge prism. The computer simulation and experimental demonstration show that this technique can be successfully applied to the Internet environment.

  6. Measurement of thin film parameters with a prism coupler.

    PubMed

    Ulrich, R; Torge, R

    1973-12-01

    The prism coupler, known from experiments on integrated optics, can be used to determine the refractive index and the thickness of a light-guiding thin film. Both parameters are obtained simultaneously and with good accuracy by measuring the coupling angles at the prism and fitting them by a theoretical dispersion curve. The fundamentals and limitations. of this method are discussed, its practical use, and mathematical procedures for the evaluation.

  7. Negligible impact on posture from 5-diopter vertical yoked prisms.

    PubMed

    Suttle, Catherine M; Asper, Lisa J; Sturnieks, Daina; Menant, Jasmine

    2015-05-01

    Yoked prisms are used by some optometrists to adjust posture, but evidence to support this practice is sparse and low level. The aim of this research was to investigate whether vertical yoked prisms have an impact on posture in healthy adults. Posture was assessed objectively in 20 healthy adults, by recording a range of joint angles or body segment locations at the ankle, hip, torso, neck, and head during participant observation of a straight-ahead target, and subsequently with eyes closed. Recording occurred before, during, and after wearing goggles with control plano lenses, and 5-diopter (D) base-up and 5-D base-down yoked prisms. In each viewing condition, the goggles were worn for 30 minutes. Interaction effects of lens/prism condition by time on joint angles and body orientation were determined. In the eyes-open and eyes-closed conditions, no significant lens/prism × time interaction effects were found at the torso, neck, hip, or ankle (P > 0.1). However, in both eyes-open and eyes-closed conditions a significant lens/prism × time interaction was found at the head (P = 0.031 and 0.006, respectively), with head extended (tilted backward) by up to 2.5 degrees more while viewing with base-down prisms than with plano lenses. In healthy adults, 5-D base-down yoked prisms were not associated with a change in body posture. A small effect on head orientation and not at other locations suggests a minimal effect on posture. Research in a larger sample and in individuals with abnormal posture is needed to verify this.

  8. Wedge Prism for Direction Resolved Speckle Correlation Interferometry

    SciTech Connect

    Pechersky, M.J.

    1999-01-20

    The role of a wedge prism for strain sign determination and enhancing the sensitivity for sub-fringe changes is emphasized. The design and incorporation aspects for in-plane sensitive interferometers have been described in detail. Some experimental results dealing with stress determination by laser annealing and speckle corelation interferometry are presented. The prism can also be applied to produce standardized carrier fringes in spatial phase shifting interferometry.

  9. Acquired non-Chagas megacolon associated with the use of psychiatric medication: case report and differential diagnosis with Chagas megacolon.

    PubMed

    Adad, Sheila Jorge; Souza, Moisés Amâncio; Silva, Gisele Barbosa E; Carmo Junior, José do; Godoy, Charles Antônio Pires de; Micheletti, Adilha Misson Rua

    2008-01-01

    A case of acquired megacolon in a 62-year-old man with acute abdomen due to sigmoid volvulus is reported. The case was associated with the use of psychiatric medications. The aim in this report was to emphasize the differential diagnosis with Chagas megacolon. Anatomopathological examination did not show any evidence of denervation, ganglionitis and/or myositis, and the serological test for Chagas disease was negative.

  10. Prism coupling into clad uniform optical waveguides

    SciTech Connect

    Revelli, J.F.; Sarid, D.

    1980-07-01

    The theory of prism coupling into multilayered dielectric slab waveguides is presented. In addition to including the possibility of high index cladding, the present theory also extends the region of validity of previously reported work to cover the regime of ''strong coupling''. The limiting conditions for validity of the present theory are that both ..cap alpha../sub m//k and ..cap alpha../sub m/ +- p/k be much smaller than either unity or vertical-bar..beta../sub m/-..beta../sub m/ +- pvertical-bar, where m is the mode under consideration, ..cap alpha../sub m/ is the leakage of that mode, and vertical-bar..beta../sub m/-..beta../sub m/ +- pvertical-bar is the separation of the effective indices of adjacent modes. A numerical example is presented in which the coupling efficiency into a uniform or slab waveguide with ..delta..n=0.002 is calculated for various cladding thicknesses with a cladding index of 2.5. The introduction of cladding is found to reduce coupling efficiency in this example due to increased phase mismatch between the incident and ''ideal'' beams.

  11. PRISM: a planned risk information seeking model.

    PubMed

    Kahlor, LeeAnn

    2010-06-01

    Recent attention on health-related information seeking has focused primarily on information seeking within specific health and health risk contexts. This study attempts to shift some of that focus to individual-level variables that may impact health risk information seeking across contexts. To locate these variables, the researcher posits an integrated model, the Planned Risk Information Seeking Model (PRISM). The model, which treats risk information seeking as a deliberate (planned) behavior, maps variables found in the Theory of Planned Behavior (TPB; Ajzen, 1991) and the Risk Information Seeking and Processing Model (RISP; Griffin, Dunwoody, & Neuwirth, 1999), and posits linkages among those variables. This effort is further informed by Kahlor's (2007) Augmented RISP, the Theory of Motivated Information Management (Afifi & Weiner, 2004), the Comprehensive Model of Information Seeking (Johnson & Meischke, 1993), the Health Information Acquisition Model (Freimuth, Stein, & Kean, 1989), and the Extended Parallel Processing Model (Witte, 1998). The resulting integrated model accounted for 59% of the variance in health risk information-seeking intent and performed better than the TPB or the RISP alone.

  12. APEX - the Hyperspectral ESA Airborne Prism Experiment

    PubMed Central

    Itten, Klaus I.; Dell'Endice, Francesco; Hueni, Andreas; Kneubühler, Mathias; Schläpfer, Daniel; Odermatt, Daniel; Seidel, Felix; Huber, Silvia; Schopfer, Jürg; Kellenberger, Tobias; Bühler, Yves; D'Odorico, Petra; Nieke, Jens; Alberti, Edoardo; Meuleman, Koen

    2008-01-01

    The airborne ESA-APEX (Airborne Prism Experiment) hyperspectral mission simulator is described with its distinct specifications to provide high quality remote sensing data. The concept of an automatic calibration, performed in the Calibration Home Base (CHB) by using the Control Test Master (CTM), the In-Flight Calibration facility (IFC), quality flagging (QF) and specific processing in a dedicated Processing and Archiving Facility (PAF), and vicarious calibration experiments are presented. A preview on major applications and the corresponding development efforts to provide scientific data products up to level 2/3 to the user is presented for limnology, vegetation, aerosols, general classification routines and rapid mapping tasks. BRDF (Bidirectional Reflectance Distribution Function) issues are discussed and the spectral database SPECCHIO (Spectral Input/Output) introduced. The optical performance as well as the dedicated software utilities make APEX a state-of-the-art hyperspectral sensor, capable of (a) satisfying the needs of several research communities and (b) helping the understanding of the Earth's complex mechanisms. PMID:27873868

  13. Holographic prism based on photo-thermo-refractive glass

    NASA Astrophysics Data System (ADS)

    Ivanov, S. A.; Angervaks, A. E.; Van Bac, Doan; Nikonorov, N. V.; Okun', R. A.

    2017-06-01

    New application of photo-thermo-refractive glass (PTR) named "holographic prism" is presented. In the holographic prism angles between directions are set by the holograms which create "fan" of signal beams. This kind of prism creates several signal beams which are equal to the reflections from facets of the conventional silica prism. Implementation of PTR glass as a holographic medium for this device brought us several advantages and new features. First it leads to decrease in overall size of the prism that positively affects the identification process of the beam's crosspoint. Thus, it increases sensitivity and accuracy of the measure. Second, greater value of the refractive index change in PTR glass in comparison with calcium fluoride crystal allows us to increase quantity of the recorded reference beams for the measure which leads to sensitivity increase. During this work, we established recording schedule for the PTR glass in case of the superimposed gratings recording. Was found that exposure for each grating should be equal to the 1/N fraction of the optimal exposure where N is the number of multiplexed gratings. We proved that in this case the total value of the refractive index modulation amplitude is equal to that for the single grating with optimal exposure. Considering obtained data we successfully performed recording of the holographic prism of the second modification with 14 channels.

  14. Chagas disease (American trypanosomiasis) in Mexico: an update.

    PubMed

    Carabarin-Lima, Alejandro; González-Vázquez, María Cristina; Rodríguez-Morales, Olivia; Baylón-Pacheco, Lidia; Rosales-Encina, José Luis; Reyes-López, Pedro Antonio; Arce-Fonseca, Minerva

    2013-08-01

    Chagas disease is a parasitic infection caused by the protozoan Trypanosoma cruzi, a flagellated organism that is transmitted mainly to humans through the infected feces of triatomine kissing bugs (vector transmission in endemic areas) or by transfusion of infected blood, donations of infected organ, or transmission from an infected mother to her child at birth. Chagas disease was first described in 1909 by the Brazilian physician Carlos Chagas, and due to the parasite's distribution throughout North, Central and South America, the disease is commonly known as American trypanosomiasis. However, this disease is now present in non-endemic countries such as Canada, the United States of America, and several countries in Europe (principally Spain). Moreover, Chagas disease was recently designated by the World Health Organization as one of the main neglected tropical diseases. The aim of this review is to summarize the research efforts recently described in studies conducted in Mexico on Chagas disease. In this country, there are no existing vector control programs. In addition, there is no consensus on the diagnostic methods for acute and chronic Chagas disease in maternity wards and blood banks, and trypanocidal therapy is not administered to chronic patients. The actual prevalence of the disease is unknown because no official reporting of cases is performed. Therefore, the number of people infected by different routes of transmission (vector, congenital, blood transfusion, organ transplantation, or oral) is unknown. We believe that by promoting education about Chagas disease in schools starting at the basic elementary level and including reinforcement at higher education levels will ensure that the Mexican population would be aware of this health problem and that the control measures adopted will have more acceptance and success. We hope that this review sensitizes the relevant authorities and that the appropriate measures to reduce the risk of infection by T. cruzi

  15. PRISM, Processing and Review Interface for Strong Motion Data Software

    NASA Astrophysics Data System (ADS)

    Kalkan, E.; Jones, J. M.; Stephens, C. D.; Ng, P.

    2016-12-01

    A continually increasing number of high-quality digital strong-motion records from stations of the National Strong Motion Project (NSMP) of the U.S. Geological Survey (USGS), as well as data from regional seismic networks within the U.S., calls for automated processing of strong-motion records with human review limited to selected significant or flagged records. The NSMP has developed the Processing and Review Interface for Strong Motion data (PRISM) software to meet this need. PRISM automates the processing of strong-motion records by providing batch-processing capabilities. The PRISM software is platform-independent (coded in Java), open-source, and does not depend on any closed-source or proprietary software. The software consists of two major components: a record processing engine composed of modules for each processing step, and a graphical user interface (GUI) for manual review and processing. To facilitate the use by non-NSMP earthquake engineers and scientists, PRISM (both its processing engine and GUI components) is easy to install and run as a stand-alone system on common operating systems such as Linux, OS X and Windows. PRISM was designed to be flexible and extensible in order to accommodate implementation of new processing techniques. Input to PRISM currently is limited to data files in the Consortium of Organizations for Strong-Motion Observation Systems (COSMOS) V0 format, so that all retrieved acceleration time series need to be converted to this format. Output products include COSMOS V1, V2 and V3 files as: (i) raw acceleration time series in physical units with mean removed (V1), (ii) baseline-corrected and filtered acceleration, velocity, and displacement time series (V2), and (iii) response spectra, Fourier amplitude spectra and common earthquake-engineering intensity measures (V3). A thorough description of the record processing features supported by PRISM is presented with examples and validation results. All computing features have been

  16. PRISM3 Global Paleoclimate Reconstruction: A Global Warming Data Set

    NASA Astrophysics Data System (ADS)

    Dowsett, H. J.; Chandler, M. A.; Cronin, T. M.; Dwyer, G. S.; Haywood, A. M.; Hill, D. J.; Robinson, M. M.; Salzmann, U.; Williams, M.

    2007-12-01

    The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project provides a conceptual model and synoptic view of the earth during the last interval considerably warmer than modern (3.3 to 3.0 Ma) through reconstruction of sea-surface temperature (SST) and other paleoenvironmental parameters. The first PRISM reconstruction, with its foundation in a global network of paleontological analyses, was completed in the early 1990s. Since then, several significant revisions have been released culminating in the PRISM2 data set. The primary goal of PRISM remains a better understanding of the Earth's climate system during the mid-Pliocene, and to that end, includes the development of digital data sets for use with climate models. The new PRISM3 reconstruction, slated to be released early in 2008, has revised SST fields based upon integration of previous and new faunal and floral analyses with new geochemical proxies and biomarkers, a revised vegetation/land cover data set utilizing the BIOME 4 vegetation classification scheme, 3-dimensional land ice distribution based upon ice-sheet model experiments, new sea level estimates based upon stable isotopes and bottom water temperatures, and revised sea-ice distribution. A deep ocean temperature reconstruction, PRISM3D, adds a 3- dimensional component, which can be used for initiating coupled ocean-atmosphere GCM simulations. PRISM3 is a collaborative effort between the U.S. Geological Survey (USGS), National Science Foundation (NSF), National Aeronautics and Space Administration (NASA), British Antarctic Survey (BAS), and several national and international academic institutions (Columbia University, Duke University, George Mason University, University of Leeds and University of Leicester).

  17. [Guidelines for chagas disease: Part IV. Chagas disease in immune compromised patients].

    PubMed

    Apt B, Werner; Heitmann G, Ingrid; Jercic L, M Isabel; Jotré M, Leonor; Muñoz C Del V, Patricia; Noemí H, Isabel; San Martin V, Ana M; Sapunar P, Jorge; Torres H, Marisa; Zulantay A, Inés

    2008-08-01

    A summary of different kind of immune suppressed hosts and the importance of Trypanosoma cruzi infection in this group of patients is presented. Then, most relevant aspects of immune compromised host-parasite interaction are analyzed such as the moment of acquiring the infection, immune compromise level, mechanisms of acquisition the infection and geographic region. Clinical features of primary infection and reactivation of infection in chronic Chagasic patients are described making special emphasis in solid organ transplant and BMT. Chagas disease in AIDS patients is discussed including its treatment, follow up, monitoring the immune compromise level and prophylaxis.

  18. Acute Chagas disease in El Salvador 2000-2012 - Need for surveillance and control

    PubMed Central

    Sasagawa, Emi; de Aguilar, Ana Vilma Guevara; de Ramírez, Marta Alicia Hernández; Chévez, José Eduardo Romero; Nakagawa, Jun; Cedillos, Rafael Antonio; Kita, Kiyoshi

    2014-01-01

    Several parasitological studies carried out in El Salvador between 2000-2012 showed a higher frequency of acute cases of Chagas disease than that in other Central American countries. There is an urgent need for improved Chagas disease surveillance and vector control programs in the provinces where acute Chagas disease occurs and throughout El Salvador as a whole. PMID:24676660

  19. Acute Chagas disease in El Salvador 2000-2012 - need for surveillance and control.

    PubMed

    Sasagawa, Emi; Aguilar, Ana Vilma Guevara de; Ramírez, Marta Alicia Hernández de; Chévez, José Eduardo Romero; Nakagawa, Jun; Cedillos, Rafael Antonio; Kita, Kiyoshi

    2014-04-01

    Several parasitological studies carried out in El Salvador between 2000-2012 showed a higher frequency of acute cases of Chagas disease than that in other Central American countries. There is an urgent need for improved Chagas disease surveillance and vector control programs in the provinces where acute Chagas disease occurs and throughout El Salvador as a whole.

  20. Antioxidant small phenolic ingredients in Inonotus obliquus (persoon) Pilat (Chaga).

    PubMed

    Nakajima, Yuki; Sato, Yuzo; Konishi, Tetsuya

    2007-08-01

    Inonotus obliquus (persoon) Pilat (Chaga, in Russia, kabanoanatake in Japan) is a fungus having been used as a folk medicine in Russia and said to have many health beneficial functions such as immune modulating and anti-cancer activities. In the present study, the antioxidant activity of hot water extract (decoction) of Chaga was precisely compared with those of other medicinal fungi (Agaricus blazei Mycelia, Ganoderma lucidum and Phellinus linteus) showing Chaga had the strongest antioxidant activity among fungi examined in terms of both superoxide and hydroxyl radicals scavenging activities. Further determination of the antioxidant potential of isolated fruiting body (brown part) and Sclerotium (black part) revealed the 80% MeOH extract of fruiting body had the highest potential as high as that of Chaga decoction. Finally, seven antioxidant components were isolated and purified from the 80% MeOH extract of Chaga fruiting body, and their chemical structures were determined as small phenolics as follows: 4-hydroxy-3,5-dimethoxy benzoic acid 2-hydroxy-1-hydroxymethyl ethyl ester (BAEE), protocatechic acid (PCA), caffeic acid (CA), 3,4-dihybenzaladehyde (DB), 2,5-dihydroxyterephtalic acid (DTA), syringic acid (SA) and 3,4-dihydroxybenzalacetone (DBL). Notably, BAEE was assigned as the new compound firstly identified from the natural source in the present study.

  1. Perspectives on Trypanosoma cruzi-induced heart disease (Chagas disease)

    PubMed Central

    Tanowitz, Herbert B.; Machado, Fabiana S.; Jelicks, Linda A.; Shirani, Jamshid; Campos de Carvalho, Antonio C.; Spray, David C.; Factor, Stephen M.; Kirchhoff, Louis V.; Weiss, Louis M.

    2009-01-01

    Chagas disease is caused by the parasite Trypanosoma cruzi it is the most common cause of heart disease in endemic areas of Latin America. The year 2009 marks the 100th anniversary of the discovery of T. cruzi infection and Chagas disease by the Brazilian physician Carlos Chagas. Chagasic cardiomyopathy develops in from 10 to 30 percent of persons who are chronically infected with this parasite. Echocardiography and magnetic resonance imaging are important modalities in the evaluation and prognosis of individuals with chagasic heart disease. The etiology of chagasic heart disease likely is multifactorial. Parasite persistence, autoimmunity, and microvascular abnormalities have been studied extensively as possible pathogenic mechanisms. Experimental studies suggest that alterations in cardiac gap junctions may be etiologic in the pathogenesis of conduction abnormalities. The diagnosis of chronic Chagas disease is made by serology. The treatment of this infection has shortcomings that need to be addressed. Cardiac transplantation and bone marrow stem cell therapy for persons with Chagas disease have received increasing research attention in recent years. PMID:19410685

  2. Functional IL18 polymorphism and susceptibility to Chronic Chagas Disease.

    PubMed

    Nogueira, Luciana Gabriel; Frade, Amanda Farage; Ianni, Barbara Maria; Laugier, Laurie; Pissetti, Cristina Wide; Cabantous, Sandrine; Baron, Monique; Peixoto, Gisele de Lima; Borges, Ariana de Melo; Donadi, Eduardo; Marin-Neto, José A; Schmidt, André; Dias, Fabrício; Saba, Bruno; Wang, Hui-Tzu Lin; Fragata, Abilio; Sampaio, Marcelo; Hirata, Mario Hiroyuki; Buck, Paula; Mady, Charles; Martinelli, Martino; Lensi, Mariana; Siqueira, Sergio Freitas; Pereira, Alexandre Costa; Rodrigues, Virmondes; Kalil, Jorge; Chevillard, Christophe; Cunha-Neto, Edecio

    2015-05-01

    Chronic Chagas Disease cardiomyopathy (CCC), a life-threatening inflammatory dilated cardiomyopathy, affects 30% of the approximately 8 million patients infected by Trypanosoma cruzi, the rest of the infected subjects remaining asymptomatic (ASY). The Th1 T cell-rich myocarditis plays a pivotal role in CCC pathogenesis. Local expression of IL-18 in CCC myocardial tissue has recently been described. IL-18 could potentially amplify the process by inducing increased expression of IFN-γ which in turn can increase the production of IL-18, thereby creating a positive feedback mechanism. In order to assess the contribution of the IL-18 to susceptibility to Chronic Chagas Disease, we investigated the association between a single nucleotide polymorphism (SNP) located in the IL-18 gene with the risk of developing Chagas cardiomyopathy. We analyzed the rs2043055 marker in the IL18 gene in a cohort of Chagas disease cardiomyopathy patients (n=849) and asymptomatic subjects (n=202). We found a significant difference in genotype frequencies among moderate and severe CCC patients with ventricular dysfunction. Our analysis suggests that the IL18 rs2043055 polymorphism- or a SNP in tight linkage disequilibrium with it- may contribute to modulating the Chagas cardiomyopathy outcome. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Cholinesterase inhibition reduces arrhythmias in asymptomatic Chagas disease.

    PubMed

    Castro, Renata R T; Porphirio, Graciema; Xavier, Sergio S; Moraes, Ruy S; Ferlin, Elton L; Ribeiro, Jorge P; da Nóbrega, Antonio C L

    2017-10-01

    Parasympathetic dysfunction may play a role in the genesis of arrhythmias in Chagas disease. This study evaluates the acute effects of pyridostigmine (PYR), a reversible cholinesterase inhibitor, on the occurrence of arrhythmias in patients with Chagas cardiac disease. Following a double-blind, randomized, placebo-controlled, cross-over protocol, 17 patients (age 50±2 years) with Chagas cardiac disease type B underwent 24-hour Holter recordings after oral administration of either pyridostigmine bromide (45 mg, 3 times/day) or placebo (PLA). Pyridostigmine reduced the 24-hours incidence (median [25%-75%]) of premature ventricular beats-PLA: 2998 (1920-4870), PYR: 2359 (940-3253), P=.044; ventricular couplets-PLA: 84 (15-159), PYR: 33 (6-94), P=.046. Although the total number of nonsustained ventricular tachycardia in the entire group was not different (P=.19) between PLA (1 [0-8]) and PYR (0 [0-4]), there were fewer episodes under PYR in 72% of the patients presenting this type of arrhythmia (P=.033). Acute administration of pyridostigmine reduced the incidence of nonsustained ventricular arrhythmias in patients with Chagas cardiac disease. Further studies that address the use of pyridostigmine by patients with Chagas cardiac disease under a more prolonged follow-up are warranted. © 2017 John Wiley & Sons Ltd.

  4. Cerebellar lesions and prism adaptation in macaque monkeys.

    PubMed

    Baizer, J S; Kralj-Hans, I; Glickstein, M

    1999-04-01

    If a laterally displacing prism is placed in front of one eye of a person or monkey with the other eye occluded, they initially will point to one side of a target that is located directly in front of them. Normally, people and monkeys adapt easily to the displaced vision and correct their aim after a few trials. If the prism then is removed, there is a postadaptation shift in which the subject misses the target and points in the opposite direction for a few trials. We tested five Macaque monkeys for their ability to adapt to a laterally displacing prism and to show the expected postadaptation shift. When tested as normals, all five animals showed the typical pattern of adaptation and postadaptation shift. Like human subjects, the monkeys also showed complete interocular transfer of the adaptation but no transfer of the adaptation between the two arms. When preoperative training and testing was complete, we made lesions of various target areas on the cerebellar cortex. A cerebellar lesion that included the dorsal paraflocculus and uvula abolished completely the normal prism adaptation for the arm ipsilateral to the lesion in one of the five monkeys. The other four animals retained the ability to prism-adapt normally and showed the expected postadaptation shift. In the one case in which the lesion abolished prism adaptation, the damage included Crus I and II, paramedian lobule and the dorsal paraflocculus of the cerebellar hemispheres as well as lobule IX, of the vermis. Thus in this case, the lesion included virtually all the cerebellar cortex that receives mossy-fiber visual information relayed via the pontine nuclei from the cerebral cortex. The other four animals had damage to lobule V, the classical anterior lobe arm area and/or vermian lobules VI/VII, the oculomotor region. When tested postoperatively, some of these animals showed a degree of ataxia equivalent to that of the case in which prism adaptation was affected, but prism adaptation and the

  5. Study of dose calculation on breast brachytherapy using prism TPS

    NASA Astrophysics Data System (ADS)

    Fendriani, Yoza; Haryanto, Freddy

    2015-09-01

    PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm3. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm3. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy.

  6. Genomes to natural products PRediction Informatics for Secondary Metabolomes (PRISM).

    PubMed

    Skinnider, Michael A; Dejong, Chris A; Rees, Philip N; Johnston, Chad W; Li, Haoxin; Webster, Andrew L H; Wyatt, Morgan A; Magarvey, Nathan A

    2015-11-16

    Microbial natural products are an invaluable source of evolved bioactive small molecules and pharmaceutical agents. Next-generation and metagenomic sequencing indicates untapped genomic potential, yet high rediscovery rates of known metabolites increasingly frustrate conventional natural product screening programs. New methods to connect biosynthetic gene clusters to novel chemical scaffolds are therefore critical to enable the targeted discovery of genetically encoded natural products. Here, we present PRISM, a computational resource for the identification of biosynthetic gene clusters, prediction of genetically encoded nonribosomal peptides and type I and II polyketides, and bio- and cheminformatic dereplication of known natural products. PRISM implements novel algorithms which render it uniquely capable of predicting type II polyketides, deoxygenated sugars, and starter units, making it a comprehensive genome-guided chemical structure prediction engine. A library of 57 tailoring reactions is leveraged for combinatorial scaffold library generation when multiple potential substrates are consistent with biosynthetic logic. We compare the accuracy of PRISM to existing genomic analysis platforms. PRISM is an open-source, user-friendly web application available at http://magarveylab.ca/prism/.

  7. The Program for Regional and International Shorebird Monitoring (PRISM)

    USGS Publications Warehouse

    Bart, J.; Andres, B.; Brown, S.; Donaldson, G.; Harrington, B.; Johnston, V.; Jones, S.; Morrison, R.I.G.; Skagen, S.K.

    2005-01-01

    This report describes the a??Program for Regional and International Shorebird Monitoringa?? (PRISM). PRISM is being implemented by a Canada-United States Shorebird Monitoring and Assessment Committee formed in 2001 by the Canadian Shorebird Working Group and the U.S. Shorebird Council. PRISM provides a single blueprint for implementing the shorebird conservation plans recently completed in Canada and the United States. The goals of PRISM are to (1) estimate the size of breeding population of 74 shorebird taxa in North America; (2) describe the distribution, abundance, and habitat relationships for each of these taxa; (3) monitor trends in shorebird population size; (4) monitor shorebird numbers at stopover locations, and; (5) assist local managers in meeting their shorebird conservation goals. PRISM has four main components: arctic and boreal breeding surveys, temperate breeding surveys, temperate non-breeding surveys, and neotropical surveys. Progress on, and action items for, each major component are described. The more important major tasks for immediate action are carrying out the northern surveys, conducting regional analyses to design the program of migration counts, and evaluating aerial photographic surveys for migration and winter counts.

  8. Adaptation to Leftward Shifting Prisms Alters Motor Interhemispheric Inhibition.

    PubMed

    Martín-Arévalo, Elisa; Schintu, Selene; Farnè, Alessandro; Pisella, Laure; Reilly, Karen T

    2016-12-18

    Adaptation to rightward shifting prisms (rightward prism adaptation, RPA) ameliorates neglect symptoms in patients while adaptation to leftward shifting prisms (leftward prism adaptation, LPA) induces neglect-like behaviors in healthy subjects. It has been hypothesized that prism adaptation (PA) modulates interhemispheric balance between the parietal cortices by inhibiting the posterior parietal cortex (PPC) contralateral to the prismatic deviation, but PA's effects on interhemispheric inhibition (IHI) have not been directly investigated. Since there are hyper-excitable connections between the PPC and primary motor cortex (M1) in the left hemisphere of neglect patients, we reasoned that LPA might mimic right hemisphere lesions by reducing parietal IHI, hyper-exciting the left PPC and PPC-M1 connections, and in turn altering IHI at the motor level. Namely, we hypothesized that LPA would increase IHI from the left to the right M1. We examined changes in left-to-right and right-to-left IHI between the 2 M1s using the ipsilateral silent period (iSP) (Meyer et al. 1995) before and after either LPA or RPA. The iSP was significantly longer after LPA but only from left-to-right and it did not change at all after RPA. This is the first physiological demonstration that LPA alters IHI in the healthy brain. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Research on beam splitting prism in laser heterodyne interferometer

    NASA Astrophysics Data System (ADS)

    Fu, Xiu-hua; Xiong, Shi-fu; Kou, Yang; Pan, Yong-gang; Chen, Heng; Li, Zeng-yu; Zhang, Chuan-xin

    2014-08-01

    With the rapid development of optical testing technology, laser heterodyne interferometer has been used more and more widely. As the testing precision requirements continue to increase, the technical prism is an important component of heterodyne interference. The research utilizing thin film technology to improve optical performance of interferometer has been a new focus. In the article, based on the use requirements of interferometer beam splitting prism, select Ta2O5 and SiO2 as high and low refractive index materials respectively, deposit on substrate K9. With the help of TFCalc design software and Needle method, adopting electron gun evaporation and ion assisted deposition, the beam splitting prism is prepared successfully and the ratio of transmittance and reflectance for this beam splitting prism in 500~850 nm band, incident angle 45 degree is 8:2. After repeated tests, solved the difference problem of film deposition process parameters ,controlled thickness monitoring precision effectively and finally prepared the ideal beam splitting prism which is high adhesion and stable optics properties. The film the laser induced damage threshold and it meet the requirements of heterodyne interferometer for use.

  10. Prism adaptation and unilateral neglect: review and analysis.

    PubMed

    Redding, Gordon M; Wallace, Benjamin

    2006-01-01

    Theory and data from normal prism adaptation are applied toward understanding the ameliorating effects of prism adaptation for left unilateral neglect patients. Neglect is proposed to be, at least in part, a dysfunction in selection of the region of space appropriate for the task at hand. Normally, a task-work space is strategically sized and positioned (calibrated) around the task-relevant objects. Patients show deficits in both strategic abilities: the task-work space is pathologically reduced in size and patients cannot strategically shift its position. Prism adaptation (spatial realignment) ameliorates dysfunctional positioning, but not sizing of the task-work space. Realignment shifts the egocentric coordinates of a sensory-motor reference frame, thereby bringing at least part of the neglected hemispace into the dysfunctional task-work space: prism adaptation substitutes for dysfunctional positioning, but not sizing of a task-work space. However, such amelioration of dysfunctional positioning may enable relearning of strategic processes (calibration), perhaps, even partially restoring the ability to appropriately size the task-space. Investigation of therapeutic prism adaptation requires methods that permit identification of both the calibration dysfunction and ameliorating realignment.

  11. Stress effects in prism coupling measurements of thin polymer films

    NASA Astrophysics Data System (ADS)

    Agan, S.; Ay, F.; Kocabas, A.; Aydinli, A.

    2005-02-01

    Due to the increasingly important role of some polymers in optical waveguide technologies, precise measurement of their optical properties has become important. Typically, prism coupling to slab waveguides made of materials of interest is used to measure the relevant optical parameters. However, such measurements are often complicated by the softness of the polymer films when stress is applied to the prism to couple light into the waveguides. In this work, we have investigated the optical properties of three different polymers, polystyrene (PS), polymethyl-methacrylate (PMMA), and benzocyclobutane (BCB). For the first time, the dependence of the refractive index, film thickness, and birefringence on applied stress in these thin polymer films was determined by means of the prism coupling technique. Both symmetric trapezoid shaped and right-angle prisms were used to couple the light into the waveguides. It was found that trapezoid shaped prism coupling gives better results in these thin polymer films. The refractive index of PMMA was found to be in the range of 1.4869 up to 1.4876 for both TE and TM polarizations under the applied force, which causes a small decrease in the film thickness of up to 0.06 μm. PMMA waveguide films were found not to be birefringent. In contrast, both BCB and PS films exhibit birefringence albeit of opposing signs.

  12. Genomes to natural products PRediction Informatics for Secondary Metabolomes (PRISM)

    PubMed Central

    Skinnider, Michael A.; Dejong, Chris A.; Rees, Philip N.; Johnston, Chad W.; Li, Haoxin; Webster, Andrew L. H.; Wyatt, Morgan A.; Magarvey, Nathan A.

    2015-01-01

    Microbial natural products are an invaluable source of evolved bioactive small molecules and pharmaceutical agents. Next-generation and metagenomic sequencing indicates untapped genomic potential, yet high rediscovery rates of known metabolites increasingly frustrate conventional natural product screening programs. New methods to connect biosynthetic gene clusters to novel chemical scaffolds are therefore critical to enable the targeted discovery of genetically encoded natural products. Here, we present PRISM, a computational resource for the identification of biosynthetic gene clusters, prediction of genetically encoded nonribosomal peptides and type I and II polyketides, and bio- and cheminformatic dereplication of known natural products. PRISM implements novel algorithms which render it uniquely capable of predicting type II polyketides, deoxygenated sugars, and starter units, making it a comprehensive genome-guided chemical structure prediction engine. A library of 57 tailoring reactions is leveraged for combinatorial scaffold library generation when multiple potential substrates are consistent with biosynthetic logic. We compare the accuracy of PRISM to existing genomic analysis platforms. PRISM is an open-source, user-friendly web application available at http://magarveylab.ca/prism/. PMID:26442528

  13. Prism sodium-cooled reactor design and performance

    SciTech Connect

    Kwant, W.; Magee, P.M.; Patel, M.R. )

    1989-01-01

    The Power Reactor Inherently Safe Module (PRISM) program is being conducted at General Electric (GE) under U.S. Department of Energy sponsorship to develop a conceptual design for an advanced sodium-cooled liquid-metal reactor plant. The PRISM design emphasizes inherent safety, modular construction, and factory fabrication. A PRISM power plant includes a number of reactor modules, which will be fabricated in a factory and shipped by whatever combination of barge, rail, and road transport that is most economical for a particular site. The target commercial PRISM plant utilizes nine reactor modules arranged in three identical 465-MW(electric) power blocks for an overall plant net electrical rating of 1395 MW(electric). Each power block has three identical reactor modules, each with its own steam generator, that jointly supply saturated steam to a single turbine generator. The PRISM's features of fewer and simpler safety systems, seismic isolation, passive decay heat removal, inherent reactivity control, and generous margins from structural and fuel damage limits during potential accident situations will result in significant gains in public safety and protection of the owner's investment. The use of standardized modular construction and extensive factory fabrication is resulting in a plant design that is economically competitive against projected coal plants and other nuclear design approaches.

  14. PRISM: A Practical Mealtime Imaging Stereo Matcher

    NASA Astrophysics Data System (ADS)

    Nishihara, H. K.

    1984-02-01

    A fast stereo-matching algorithm designed to operate in the presence of noise is described. The algorithm has its roots in the zero-crossing theory of Marr and Poggio but does not explicitly match zero-crossing contours. While these contours are for the most part stably tied to fixed surface locations, some fraction is always perturbed significantly by system noise. Zero-crossing contour based matching algorithms tend to I- very sensitive to these local distortions and ar, prevented from operating well on signals with moderate noise levels even though a substantial amount of information may still be present. The dual representation ¬â€?regions of constant sign in the V2G convolution persist much further into the noise than does the local geometry of the zero-crossing contours that delimit them. The PRISM system was designed to test this approach. The initial design task of the implementation has been to rapidly detect obstacles in a robotics work space and determine their rough extents and heights. In this case speed and reliability are important but precision is less critical. The system uses a pair of inexpensive vidicon cameras mounted above the workspace of a PUMA robot manipulator. The digitized video signals are fed to a high speed digital convolver that applies a 322 VG operator to the images at a 106 pixel per second rate. Matching is accomplished in software on a lisp machine with individual near/far tests taking less than i3luth of a second. A 36 by 26 matrix of absolute height measurements - in mm - over a 100 pixel disparity range is produced in 30 seconds from image acquisition to final output. Three scales of resolution are used in a coarse guides fine search. Acknowledgment: This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of 'Technology Support for the laboratory's artificial intelligence research is provided in part by the Advanced Research Projects Agency of the Department of Defense

  15. Chagas' disease and ageing: the coexistence of other chronic diseases with Chagas' disease in elderly patients.

    PubMed

    Alves, Rosalía Matera de Angelis; Thomaz, Raquel Prado; Almeida, Eros Antônio de; Wanderley, Jamiro da Silva; Guariento, Maria Elena

    2009-01-01

    This study aimed to identify the main comorbidities in elderly chagasic patients treated in a reference service and identify possible associations between the clinical form of Chagas' disease and chronic diseases. Ninety patients aged 60 years-old or over were interviewed and their clinical diagnoses recorded. The study population profile was: women (55.6%); median age (67 years); married (51.1%); retired (73.3%); up to four years' education (64.4%); and earning less than two minimum wages (67.8%). The predominant forms of Chagas' disease were the cardiac (46.7%) and mixed forms (30%). There was a greater proportion of mild cardiac dysfunction (84.1%), frequently in association with megaesophagus. The mean number of concurrent diseases was 2.856 +/- 1.845, and 33% of the patients had four or more comorbidities. The most frequent were systemic arterial hypertension (56.7%), osteoporosis (23.3%), osteoarthritis (21.2%) and dyslipidemia (20%). Positive correlations were verified between sex and comorbidities and between age group and comorbidities.

  16. Epidemiology of American trypanosomiasis (Chagas disease).

    PubMed

    Kirchhoff, Louis V

    2011-01-01

    Trypanosoma cruzi, the cause of American trypanosomiasis, or Chagas disease, is a protozoan parasite that is enzootic and endemic in much of the Americas, where it infects a wide variety of wild and domestic mammals as well as many species of triatomine vectors, in addition to humans. Historically, vector-borne transmission of T. cruzi has been the most important mechanism through which humans have become infected with the parasite, but transmission by blood transfusion and congenital transmission also have been important. In many of the endemic countries transmission of T. cruzi has improved markedly in recent years as vector control and donor screening programs have been implemented on a widespread basis. In the United States autochthonous transmission of T. cruzi appears to be extremely rare. Five persons are known to have become infected with T. cruzi through organ transplants here, and prior to the implementation of blood donor screening in 2007 five instances of transmission by transfusion had been reported. Current estimates put the total number of T. cruzi-infected persons living in the United States at 300,000, essentially all of whom are immigrants from the endemic countries. The obstacles that stand in the way of the total elimination of T. cruzi transmission throughout the endemic range are economic and political, and no major technological advances are needed to accomplish this goal. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Highly Effective Serodiagnosis for Chagas' Disease ▿

    PubMed Central

    Hernández, Pilar; Heimann, Michael; Riera, Cristina; Solano, Marco; Santalla, José; Luquetti, Alejandro O.; Beck, Ewald

    2010-01-01

    Many proteins of Trypanosoma cruzi, the causative agent of Chagas' disease, contain characteristic arrays of highly repetitive immunogenic amino acid motifs. Diagnostic tests using these motifs in monomeric or dimeric form have proven to provide markedly improved specificity compared to conventional tests based on crude parasite extracts. However, in many cases the available tests still suffer from limited sensitivity. In this study we produced stable synthetic genes with maximal codon variability for the four diagnostic antigens, B13, CRA, TcD, and TcE, each containing between three and nine identical amino acid repeats. These genes were combined by linker sequences encoding short proline-rich peptides, giving rise to a 24-kDa fusion protein which was used as a novel diagnostic antigen in an enzyme-linked immunosorbent assay setup. Validation of the assay with a large number of well-characterized patient sera from Bolivia and Brazil revealed excellent diagnostic performance. The high sensitivity of the new test may allow future studies to use blood collected by finger prick and dried on filter paper, thus dramatically reducing the costs and effort for the detection of T. cruzi infection. PMID:20668136

  18. Behavioural biology of Chagas disease vectors

    PubMed Central

    Lazzari, Claudio Ricardo; Pereira, Marcos Horácio; Lorenzo, Marcelo Gustavo

    2013-01-01

    Many arthropod species have adopted vertebrate blood as their main food source. Blood is rich in nutrients and, except for the presence of parasites, sterile. However, this food source is not freely available, nor is obtaining it devoid of risk. It circulates inside vessels hidden underneath the skin of mobile hosts that are able to defend themselves and even predate the insects that try to feed on them. Thus, the haematophagous lifestyle is associated with major morphological, physiological and behavioural adaptations that have accumulated throughout the evolutionary history of the various lineages of blood-sucking arthropods. These adaptations have significant consequences for the evolution of parasites as well as for the epidemiology of vector-transmitted diseases. In this review article, we analyse various aspects of the behaviour of triatomine bugs to illustrate how each behavioural trait represents a particular adaptation to their close association with their hosts, which may easily turn into predators. Our aim is to offer to the reader an up-to-date integrative perspective on the behaviour of Chagas disease vectors and to propose new research avenues to encourage both young and experienced colleagues to explore this aspect of triatomine biology. PMID:24473801

  19. Novel cruzipain inhibitors for the chemotherapy of chronic Chagas disease.

    PubMed

    Sbaraglini, María L; Bellera, Carolina L; Fraccaroli, Laura; Larocca, Luciana; Carrillo, Carolina; Talevi, Alan; Alba Soto, Catalina D

    2016-07-01

    Despite current efforts worldwide to develop new medications against Chagas disease, only two drugs are available, nifurtimox and benznidazole. Both drugs require prolonged treatment and have multiple side effects and limited efficacy on adult patients chronically infected with Trypanosoma cruzi. Recently, computer-guided drug repositioning led to the discovery of the trypanocidal effects of clofazimine and benidipine. These compounds showed inhibitory effects on cruzipain, the major cysteine protease of T. cruzi, of different parasite stages and in a murine model of acute Chagas disease. The aim of this work was to determine the efficacy of these novel cruzipain inhibitors when administered in a murine model of chronic Chagas disease. Benidipine and clofazimine were able to reduce the parasite burden in cardiac and skeletal muscles of chronically infected mice compared with untreated mice as well as diminish the inflammatory process in these tissues. Further studies should be performed to study the synergism with benznidazole and nifurtimox in view of combined therapies.

  20. Would selenium supplementation aid in therapy for Chagas Disease?

    PubMed Central

    Jelicks, Linda A.; de Souza, Andréa P.; Araújo-Jorge, Tania C; Tanowitz, Herbert B.

    2010-01-01

    Chagas disease, a neglected tropical disease discovered over 100 years ago, is caused by the intracellular parasite Trypanosoma cruzi and is most frequently associated with chronic cardiomyopathy and digestive disorders. Initial invasion of cells is followed by progressive inflammatory destruction of heart, muscles, nerves, and gastrointestinal (GI) tract tissue. About 30% of patients progress to a chronic cardiomyopathy associated with increased morbidity and mortality. Seven to 10% of patients develop megasyndromes involving the GI tract, in particular, the esophagus and the colon. Results from several studies suggest that selenium (Se) deficiency may be an important factor in the pathogenesis of Chagas disease. In this opinion article, Se supplementation is proposed as an adjuvant therapy for treatment of chronic Chagas disease. PMID:21212020

  1. Biologic and Genetics Aspects of Chagas Disease at Endemic Areas

    PubMed Central

    Bellini, Marilanda Ferreira; Silistino-Souza, Rosana; Varella-Garcia, Marileila; de Azeredo-Oliveira, Maria Tercília Vilela; Silva, Ana Elizabete

    2012-01-01

    The etiologic agent of Chagas Disease is the Trypanosoma cruzi, transmitted through blood-sucking insect vectors of the Triatominae subfamily, representing one of the most serious public health concerns in Latin America. There are geographic variations in the prevalence of clinical forms and morbidity of Chagas disease, likely due to genetic variation of the T. cruzi and the host genetic and environmental features. Increasing evidence has supported that inflammatory cytokines and chemokines are responsible for the generation of the inflammatory infiltrate and tissue damage. Moreover, genetic polymorphisms, protein expression levels, and genomic imbalances are associated with disease progression. This paper discusses these key aspects. Large surveys were carried out in Brazil and served as baseline for definition of the control measures adopted. However, Chagas disease is still active, and aspects such as host-parasite interactions, genetic mechanisms of cellular interaction, genetic variability, and tropism need further investigations in the attempt to eradicate the disease. PMID:22529863

  2. VNI Cures Acute and Chronic Experimental Chagas Disease

    PubMed Central

    Villalta, Fernando; Dobish, Mark C.; Nde, Pius N.; Kleshchenko, Yulia Y.; Hargrove, Tatiana Y.; Johnson, Candice A.; Waterman, Michael R.; Johnston, Jeffrey N.; Lepesheva, Galina I.

    2013-01-01

    Chagas disease is a deadly infection caused by the protozoan parasite Trypanosoma cruzi. Afflicting approximately 8 million people in Latin America, Chagas disease is now becoming a serious global health problem proliferating beyond the traditional geographical borders, mainly because of human and vector migration. Because the disease is endemic in low-resource areas, industrial drug development has been lethargic. The chronic form remains incurable, there are no vaccines, and 2 existing drugs for the acute form are toxic and have low efficacy. Here we report the efficacy of a small molecule, VNI, including evidence of its effectiveness against chronic Chagas disease. VNI is a potent experimental inhibitor of T. cruzi sterol 14α-demethylase. Nontoxic and highly selective, VNI displays promising pharmacokinetics and administered orally to mice at 25 mg/kg for 30 days cures, with 100% cure rate and 100% survival, the acute and chronic T. cruzi infection. PMID:23372180

  3. Chagas Heart Failure in Patients from Latin America

    PubMed Central

    2016-01-01

    Physicians working in Europe and the United States should suspect Chagas heart failure in every patient coming from Latin America with chronic heart failure. Diagnosis should be confirmed by positive serology. Right bundle branch block and left anterior fascicular block on 12-lead electrocardiogram, enlarged cardiac silhouette with no pulmonary congestion on chest X-ray and left ventricular apical aneurysm on echocardiography are the distinctive features of this condition. The clinical course is poorer than that of non-Chagas heart failure; however, medical treatment is similar. Implantable cardioverter-defibrillators are useful in the primary and secondary prevention of sudden cardiac death. Cardiac resynchronisation therapy can be given to patients on optimal medical therapy and with lengthened QRS complex. Heart transplantation is the treatment of choice for patients with end-stage Chagas heart failure. PMID:28785459

  4. Gallbladder neuron count in cholelithiasis patients with and without Chagas disease.

    PubMed

    Crema, Eduardo; Ribeiro, Lara Beatriz Prata; Adad, Sheila Jorge; Ectchebehere, Renata Margarida; Martins Júnior, Aiodair; Silva, Alex Augusto

    2007-01-01

    Various investigators agree that the incidence of cholelithiasis is greater in patients with Chagas disease. The most plausible explanation for this is based on the parasympathetic denervation that occurs over the whole digestive tract due to Chagas disease. In order to analyze the occurrence of this alteration, gallbladder neuron counts were performed on cholelithiasis patients with and without Chagas disease who were being treated at the Department of Digestive Surgery, Universidade Federal do Triângulo Mineiro, Uberaba, Brazil. In the present study, a notable reduction in the number of neurons in the gallbladder wall was observed in Chagas patients, in comparison with non-Chagas subjects.

  5. The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction

    NASA Astrophysics Data System (ADS)

    Dowsett, Harry; Dolan, Aisling; Rowley, David; Moucha, Robert; Forte, Alessandro M.; Mitrovica, Jerry X.; Pound, Matthew; Salzmann, Ulrich; Robinson, Marci; Chandler, Mark; Foley, Kevin; Haywood, Alan

    2016-07-01

    The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian ( ˜ 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments.

  6. High resolution neutron Larmor diffraction using superconducting magnetic Wollaston prisms.

    PubMed

    Li, Fankang; Feng, Hao; Thaler, Alexander N; Parnell, Steven R; Hamilton, William A; Crow, Lowell; Yang, Wencao; Jones, Amy B; Bai, Hongyu; Matsuda, Masaaki; Baxter, David V; Keller, Thomas; Fernandez-Baca, Jaime A; Pynn, Roger

    2017-04-13

    The neutron Larmor diffraction technique has been implemented using superconducting magnetic Wollaston prisms in both single-arm and double-arm configurations. Successful measurements of the coefficient of thermal expansion of a single-crystal copper sample demonstrates that the method works as expected. The experiment involves a new method of tuning by varying the magnetic field configurations in the device and the tuning results agree well with previous measurements. The difference between single-arm and double-arm configurations has been investigated experimentally. We conclude that this measurement benchmarks the applications of magnetic Wollaston prisms in Larmor diffraction and shows in principle that the setup can be used for inelastic phonon line-width measurements. The achievable resolution for Larmor diffraction is comparable to that using Neutron Resonance Spin Echo (NRSE) coils. The use of superconducting materials in the prisms allows high neutron polarization and transmission efficiency to be achieved.

  7. The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction

    USGS Publications Warehouse

    Dowsett, Harry J.; Dolan, Aisling M.; Rowley, David; Moucha, Robert; Forte, Alessandro; Mitrovica, Jerry X.; Pound, Matthew; Salzmann, Ulrich; Robinson, Marci M.; Chandler, Mark; Foley, Kevin M.; Haywood, Alan M.

    2016-01-01

    The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian ( ∼ 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments.

  8. Enhanced scanning agility using a double pair of Risley prisms.

    PubMed

    Roy, Gilles; Cao, Xiaoying; Bernier, Robert; Roy, Simon

    2015-12-01

    Scanners with one pair of Risley prisms are robust and precise and they can be operated continuously. In this paper, we present a new scanner based on the use of two pairs of Risley prisms. The concept was driven by the need to add flexibility to Risley prism scanners used for lidar 3D mapping applications, while maintaining compactness and robustness. The first pair covers a FOV narrower than the second pair. The second pair is used to position the first Risley pair scan pattern anywhere within its own, larger, FOV. Doing so, it becomes possible, without additional scanner components, to increase the sampling point density at a specific location, to increase the sampling uniformity of the scanned area, and, while in motion, to maintain the sampling of a specific area of interest.

  9. Density functional theory and simulations of colloidal triangular prisms.

    PubMed

    Marechal, Matthieu; Dussi, Simone; Dijkstra, Marjolein

    2017-03-28

    Nanopolyhedra form a versatile toolbox to investigate the effect of particle shape on self-assembly. Here we consider rod-like triangular prisms to gauge the effect of the cross section of the rods on liquid crystal phase behavior. We also take this opportunity to implement and test a previously proposed version of fundamental measure density functional theory (0D-FMT). Additionally, we perform Monte Carlocomputer simulations and we employ a simpler Onsager theory with a Parsons-Lee correction. Surprisingly and disappointingly, 0D-FMT does not perform better than the Tarazona and Rosenfeld's version of fundamental measure theory (TR-FMT). Both versions of FMT perform somewhat better than the Parsons-Lee theory. In addition, we find that the stability regime of the smectic phase is larger for triangular prisms than for spherocylinders and square prisms.

  10. The PRISM4 (mid-Piacenzian) Palaeoenvironmental Reconstruction

    NASA Technical Reports Server (NTRS)

    Dowsett, Harry; Dolan, Aisling; Rowley, David; Moucha, Robert; Forte, Alessandro M.; Mitrovica, Jerry X.; Pound, Matthew; Salzmann, Ulrich; Robinson, Marci; Chandler, Mark; hide

    2016-01-01

    The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian (approximately 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments.

  11. High resolution neutron Larmor diffraction using superconducting magnetic Wollaston prisms

    DOE PAGES

    Li, Fankang; Feng, Hao; Thaler, Alexander N.; ...

    2017-04-13

    The neutron Larmor diffraction technique has been implemented using superconducting magnetic Wollaston prisms in both single-arm and double-arm configurations. Successful measurements of the coefficient of thermal expansion of a single-crystal copper sample demonstrates that the method works as expected. Our experiment involves a new method of tuning by varying the magnetic field configurations in the device and the tuning results agree well with previous measurements. The difference between single-arm and double-arm configurations has been investigated experimentally. Here, we conclude that this measurement benchmarks the applications of magnetic Wollaston prisms in Larmor diffraction and shows in principle that the setup canmore » be used for inelastic phonon line-width measurements. The achievable resolution for Larmor diffraction is comparable to that using Neutron Resonance Spin Echo (NRSE) coils. Furthermore, the use of superconducting materials in the prisms allows high neutron polarization and transmission efficiency to be achieved.« less

  12. A Prism-Mask System for Multispectral Video Acquisition.

    PubMed

    Cao, Xun; Du, Hao; Tong, Xin; Dai, Qionghai; Lin, Stephen

    2011-12-01

    This paper presents a prism-mask system for capturing multispectral videos. The system is composed of a triangular prism, a monochrome camera, and an occlusion mask. Incoming light beams from the scene are sampled by the occlusion mask, dispersed into their constituent spectra by the triangular prism, and then captured by the monochrome camera. Our system is capable of capturing frames with high spectral resolution at video rates. It also allows for different trade-offs between spectral and spatial resolution by adjusting the focal length of the camera. We demonstrate multispectral video acquisition with various spectral resolutions and spatial resolutions, as well as different frame rates. The effectiveness of our system is further evaluated with several applications, including human skin detection, physical material recognition, video segmentation, RGB video generation, and illumination identification.

  13. Symmetry breaking analysis of prism adaptation's latent aftereffect.

    PubMed

    Frank, Till D; Blau, Julia J C; Turvey, Michael T

    2012-01-01

    The effect of prism adaptation on movement is typically reduced when the movement at test (prisms off) differs on some dimension from the movement at training (prisms on). Some adaptation is latent, however, and only revealed through further testing in which the movement at training is fully reinstated. Applying a nonlinear attractor dynamic model (Frank, Blau, & Turvey, 2009) to available data (Blau, Stephen, Carello, & Turvey, 2009), we provide evidence for a causal link between the latent (or secondary) aftereffect and an additive force term that is known to account for symmetry breaking. The evidence is discussed in respect to the hypothesis that recalibration aftereffects reflect memory principles (encoding specificity, transfer-appropriate processing) oriented to time-translation invariance-when later testing conserves the conditions of earlier training. Forgetting or reduced adaptation effects follow from the loss of this invariance and are reversed by its reinstatement. Copyright © 2012 Cognitive Science Society, Inc.

  14. Interpretation of the Faust equation for a conventional refracting prism

    NASA Astrophysics Data System (ADS)

    Tewari, R. D.; Ghodgaonkar, A. M.; Gokhale, V. D.

    1995-10-01

    The Faust formula for a conventional refracting prism is interpreted in terms of the angle of incidence ( i1) and the angle of deviation (δ). Three new possibilities emerge, namely: (a) keeping the angle of incidence ( i1) constant and varying the angle of deviation (δ); (b) keeping the angle of deviation constant and varying the angle of incidence ( i1); (c) modification of the closed forms of Murty's expression and its equivalence to (b). Using paraxial approximation and keeping the angle of incidence ( i1) and angle of deviation (δ) constant we obtain a relation between the refractive index and the base length ( b) of a prism and, in principle, this is equivalent to the Marcuse variation for optical fibres. The condition for a Littrow prism, as well as for polarized radiation is derived. An expression to estimate the spectral bandwidth (SBW) of the instrument is also derived. Experimental values of refractive index at different wavelengths are within confidence limits.

  15. The Costs of Preventing and Treating Chagas Disease in Colombia

    PubMed Central

    Castillo-Riquelme, Marianela; Guhl, Felipe; Turriago, Brenda; Pinto, Nestor; Rosas, Fernando; Martínez, Mónica Flórez; Fox-Rushby, Julia; Davies, Clive; Campbell-Lendrum, Diarmid

    2008-01-01

    Background The objective of this study is to report the costs of Chagas disease in Colombia, in terms of vector disease control programmes and the costs of providing care to chronic Chagas disease patients with cardiomyopathy. Methods Data were collected from Colombia in 2004. A retrospective review of costs for vector control programmes carried out in rural areas included 3,084 houses surveyed for infestation with triatomine bugs and 3,305 houses sprayed with insecticide. A total of 63 patient records from 3 different hospitals were selected for a retrospective review of resource use. Consensus methodology with local experts was used to estimate care seeking behaviour and to complement observed data on utilisation. Findings The mean cost per house per entomological survey was $4.4 (in US$ of 2004), whereas the mean cost of spraying a house with insecticide was $27. The main cost driver of spraying was the price of the insecticide, which varied greatly. Treatment of a chronic Chagas disease patient costs between $46.4 and $7,981 per year in Colombia, depending on severity and the level of care used. Combining cost and utilisation estimates the expected cost of treatment per patient-year is $1,028, whereas lifetime costs averaged $11,619 per patient. Chronic Chagas disease patients have limited access to healthcare, with an estimated 22% of patients never seeking care. Conclusion Chagas disease is a preventable condition that affects mostly poor populations living in rural areas. The mean costs of surveying houses for infestation and spraying infested houses were low in comparison to other studies and in line with treatment costs. Care seeking behaviour and the type of insurance affiliation seem to play a role in the facilities and type of care that patients use, thus raising concerns about equitable access to care. Preventing Chagas disease in Colombia would be cost-effective and could contribute to prevent inequalities in health and healthcare. PMID:19015725

  16. Acquired Cell-Mediated Immunodepression in Acute Chagas' Disease

    PubMed Central

    Teixeira, Antonio R. L.; Teixeira, Glória; Macêdo, Vanize; Prata, Aluizio

    1978-01-01

    In this study two groups of patients with acute Chagas' disease were identified. Group one consisted of five patients with apparent acute Chagas' disease. These patients showed symptoms and signals of an acute illness, such as high fever and enlarged spleen. One of these patients developed severe myocarditis and heart failure. Group two consisted of seven patients with inapparent acute Chagas' disease. This was a nonclinical entity, not perceived by the patient who did not seek medical care. The diagnosis was made by the shift of a serologic test which indicates the presence of immunoglobulin M antibodies to Trypanosoma cruzi. The patients with apparent acute Chagas' disease showed positive delayed-type skin response to T. cruzi antigen. Also, their leukocytes showed significant inhibition of migration in the presence of this antigen. By contrast, the patients with the inapparent acute Chagas' disease did not show positive delayed-type skin response to T. cruzi antigen and no significant inhibition was observed when their cells migrated in the presence of this antigen. Of interest, none of these patients was capable of developing contact sensitivity to 2,4-dinitrochlorobenzene. However, three out of five patients with the apparent acute disease and all the normal control subjects showed positive contact reaction after sensitization to this drug. The results of these experiments would suggest that the thymus-derived (T)-lymphocyte function is depressed in patients with the clinically inapparent acute Chagas' disease. This immunodepression seems to be acquired in the course of the T. cruzi infection because all patients showed positive delayed-type skin response to at least one ubiquitous microbial extract, thus indicating previously normal T-cell function. We hypothesize that T. cruzi antigens may directly stimulate T cells with the concomitant release of factors that might become supressive for T-cell responses. Furthermore, the suppressive effect might interfere

  17. Cerebellar inactivation impairs memory of learned prism gaze-reach calibrations

    PubMed Central

    Hathaway, Emily N.; Taylor, Jordan A.; Thach, W. Thomas

    2011-01-01

    Three monkeys performed a visually guided reach-touch task with and without laterally displacing prisms. The prisms offset the normally aligned gaze/reach and subsequent touch. Naive monkeys showed adaptation, such that on repeated prism trials the gaze-reach angle widened and touches hit nearer the target. On the first subsequent no-prism trial the monkeys exhibited an aftereffect, such that the widened gaze-reach angle persisted and touches missed the target in the direction opposite that of initial prism-induced error. After 20–30 days of training, monkeys showed long-term learning and storage of the prism gaze-reach calibration: they switched between prism and no-prism and touched the target on the first trials without adaptation or aftereffect. Injections of lidocaine into posterolateral cerebellar cortex or muscimol or lidocaine into dentate nucleus temporarily inactivated these structures. Immediately after injections into cortex or dentate, reaches were displaced in the direction of prism-displaced gaze, but no-prism reaches were relatively unimpaired. There was little or no adaptation on the day of injection. On days after injection, there was no adaptation and both prism and no-prism reaches were horizontally, and often vertically, displaced. A single permanent lesion (kainic acid) in the lateral dentate nucleus of one monkey immediately impaired only the learned prism gaze-reach calibration and in subsequent days disrupted both learning and performance. This effect persisted for the 18 days of observation, with little or no adaptation. PMID:21389311

  18. Visual acuity through fresnel, refractive, and hybrid diffractive/refractive prisms.

    PubMed

    Katz, Milton

    2004-08-01

    This article compares the effect on visual acuity of the Fresnel and wedge-shaped refractive prisms with newly developed hybrid diffractive/refractive prisms (ComPrisms), which combine a wedge-shaped refractive prism with a diffractive component. The diffractive component of hybrid elements can be designed to correct the chromatic aberration of the refractive component. The monocular visual acuity of 21 subjects and binocular acuity of 20 subjects were measured with computer-generated logMAR charts. Visual acuity was measured without prisms (NP) and through ComPrisms, 3M Press-on Fresnel, and acrylic refractive prisms of 20delta, 30delta, and 40delta powers. A repeated measures analysis of variance indicates a significant main effect of treatment (without prisms and through the three types of prisms) at each prism power, both monocularly and binocularly. Results of the Scheffé test for all possible comparisons between pairs of means of the treatments are provided. Although all the prisms reduced visual acuity, the ComPrisms provide significantly better visual acuity than acrylic refractive or 3M Press-on Fresnel prisms of equivalent power

  19. Clinical and laboratory evaluation of peripheral prism glasses for hemianopia.

    PubMed

    Giorgi, Robert G; Woods, Russell L; Peli, Eli

    2009-05-01

    Homonymous hemianopia (the loss of vision on the same side in each eye) impairs the ability to navigate and walk safely. We evaluated peripheral prism glasses as a low vision optical device for hemianopia in an extended wearing trial. Twenty-three patients with complete hemianopia (13 right) with neither visual neglect nor cognitive deficit enrolled in the 5-visit study. To expand the horizontal visual field, patients' spectacles were fitted with both upper and lower Press-On Fresnel prism segments (each 40 prism diopters) across the upper and lower portions of the lens on the hemianopic ("blind") side. Patients were asked to wear these spectacles as much as possible for the duration of the study, which averaged 9 (range: 5 to 13) weeks. Clinical success (continued wear, indicating perceived overall benefit), visual field expansion, perceived direction, and perceived quality of life were measured. Clinical success: 14 of 21 (67%) patients chose to continue to wear the peripheral prism glasses at the end of the study (two patients did not complete the study for non-vision reasons). At long-term follow-up (8 to 51 months), 5 of 12 (42%) patients reported still wearing the device. Visual field expansion: expansion of about 22 degrees in both the upper and lower quadrants was demonstrated for all patients (binocular perimetry, Goldmann V4e). Perceived direction: two patients demonstrated a transient adaptation to the change in visual direction produced by the peripheral prism glasses. Quality of life: at study end, reduced difficulty noticing obstacles on the hemianopic side was reported. The peripheral prism glasses provided reported benefits (usually in obstacle avoidance) to 2/3 of the patients completing the study, a very good success rate for a vision rehabilitation device. Possible reasons for long-term discontinuation and limited adaptation of perceived direction are discussed.

  20. Clinical and Laboratory Evaluation of Peripheral Prism Glasses for Hemianopia

    PubMed Central

    Giorgi, Robert G.; Woods, Russell L.; Peli, Eli

    2008-01-01

    Purpose Homonymous hemianopia (the loss of vision on the same side in each eye) impairs the ability to navigate and walk safely. We evaluated peripheral prism glasses as a low vision optical device for hemianopia in an extended wearing trial. Methods Twenty-three patients with complete hemianopia (13 right) with neither visual neglect nor cognitive deficit enrolled in the 5-visit study. To expand the horizontal visual field, patients’ spectacles were fitted with both upper and lower Press-On™ Fresnel prism segments (each 40 prism diopters) across the upper and lower portions of the lens on the hemianopic (“blind”) side. Patients were asked to wear these spectacles as much as possible for the duration of the study, which averaged 9 (range: 5 to 13) weeks. Clinical success (continued wear, indicating perceived overall benefit), visual field expansion, perceived direction and perceived quality of life were measured. Results Clinical Success: 14 of 21 (67%) patients chose to continue to wear the peripheral prism glasses at the end of the study (2 patients did not complete the study for non-vision reasons). At long-term follow-up (8 to 51 months), 5 of 12 (42%) patients reported still wearing the device. Visual Field Expansion: Expansion of about 22 degrees in both the upper and lower quadrants was demonstrated for all patients (binocular perimetry, Goldmann V4e). Perceived Direction: Two patients demonstrated a transient adaptation to the change in visual direction produced by the peripheral prism glasses. Quality of Life: At study end, reduced difficulty noticing obstacles on the hemianopic side was reported. Conclusions The peripheral prism glasses provided reported benefits (usually in obstacle avoidance) to 2/3 of the patients completing the study, a very good success rate for a vision rehabilitation device. Possible reasons for long-term discontinuation and limited adaptation of perceived direction are discussed. PMID:19357552

  1. On the tidal prism-channel area relations

    NASA Astrophysics Data System (ADS)

    D'Alpaos, Andrea; Lanzoni, Stefano; Marani, Marco; Rinaldo, Andrea

    2010-03-01

    We verify the broad applicability of tidal prism cross-sectional area relationships, originally proposed to relate the total water volume entering a lagoon during a characteristic tidal cycle (the tidal prism) to the size of its inlet, to arbitrary sheltered cross sections within a tidal network. We suggest, with reasonable approximation defining a statistical tendency rather than a pointwise equivalence, that the regime of tidal channels may be anywhere related to local landscape-forming prisms embedded in a characteristic spring tide oscillation. The importance of the proposed extension stems from its potential for quantitative predictions of the long-term morphological evolution of whole tidal landforms, in response to forcings affecting tidal prisms. This is the case, in particular, for alterations of relative mean sea levels possibly driven by climate change. Various 1-D and 2-D morphodynamic and hydrodynamic models are employed to evaluate peak flow rates, bottom shear stresses, and the ensuing local tidal prisms. One-dimensional morphodynamic models describing both the longitudinal and cross-sectional evolution of tidal channels are used to verify the validity of the relationship for sheltered sections. Relevant hydrodynamic features determined through accurate 2-D numerical models are compared with those obtained through time-invariant equivalents, defining a mean watershed by an energy landscape from averaged free surface gradients. Empirical evidence gathered within the lagoon of Venice (Italy) supports the proposed extension. We conclude that the geomorphic law relating tidal prisms to channel cross-sectional areas anywhere within a tidal landscape is a valuable tool for studies on long-term tidal geomorphology.

  2. Polymeric waveguide prism-based electro-optic beam deflector

    NASA Astrophysics Data System (ADS)

    Sun, Lin; Kim, Jin-ha; Jang, Chiou-Hung; An, Dechang; Lu, Xuejun; Zhou, Qingjun; Taboada, John M.; Chen, Ray T.; Maki, Jeffery J.; Tang, Suning; Zhang, Hua; Steier, William H.; Zhang, Cheng H.; Dalton, Larry R.

    2001-07-01

    Beam steering devices without moving parts are highly desirable for their potential application in emerging optical technologies such as holographic optical storage systems, all optical networks, and optical switches. We demonstrate a thin-film waveguide beam deflector device that consists of an electro-optic prism array within a polymer waveguide. An electrode structure defines the prism array within the planar waveguide. The deflection efficiency of 28 mrad/kV and the maximum deflection angle of +/- 8.4 mrad at +/- 300 V are obtained for this demonstration device. Further optimization of electrode-field poling and processing is likely to improve these results by at least an order of magnitude.

  3. Chagas disease: role of parasite genetic variation in pathogenesis.

    PubMed

    Macedo, Andra M; Oliveira, Riva P; Pena, Srgio D J

    2002-03-05

    Chagas disease, caused by the parasite protozoan Trypanosoma cruzi, is characterised by a variable clinical course, from symptomless cases to severe chronic disease with cardiac and/or gastrointestinal involvement. This variability has been attributed both to differences in the host response and to genomic heterogeneity of the parasite. This article reviews the evidence in favour of an important role of the genetic constitution of T. cruzi in determining the clinical characteristics of Chagas disease and discusses the basis of the 'Clonal-Histotropic Model' for the pathogenesis of this disease.

  4. Chagas Cardiomyopathy: Clinical Presentation and Management in the Americas.

    PubMed

    Benziger, Catherine Pastorius; do Carmo, Gabriel Assis Lopes; Ribeiro, Antonio Luiz Pinho

    2017-02-01

    The initial infection of Chagas disease is typically asymptomatic, but approximately 30% of people will progress to a chronic cardiac form, and others develop the gastrointestinal form. Death is often sudden due to arrhythmias or progressive heart failure. Prevention through vector control programs and blood bank screening, along with strengthened surveillance systems and rapid information sharing, are key to decreasing disease burden globally. The epidemiology, diagnostic evaluation, diagnosis, and treatment of acute and chronic Chagas cardiac disease are discussed with focus on educating the primary care professionals and general cardiologists in nonendemic areas who have limited experience treating this disease. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Beam distortion of rotation double prisms with an arbitrary incident angle.

    PubMed

    Li, Anhu; Zuo, Qiyou; Sun, Wansong; Yi, Wanli

    2016-07-01

    The distortion of beam shape in rotation Risley prisms is discussed in this paper. Using the ray-tracing method based on vector refraction theorem, a rigorous theoretical model of beam distortion with an arbitrary incident angle is established to explore the influencing factors. For a specified double-prism pair, the emergent beam is squeezed in one direction while stretched in the mutual perpendicular direction, the distortion of which is determined by the relative rotation angle. Moreover, the distortion of beam shape is greatly influenced by the wedge angles and the refractive indices of the prisms, as well as different double-prism configurations, while uncorrelated to the prism thickness and the distance between two prisms. This paper demonstrates the regular change of the beam shape with multiparameter variations in rotation double prisms, which can be applied to the design of rotation double-prism systems.

  6. [Chagas diseases seroepidemiology in schoolchildren of Jujuy].

    PubMed

    Tortora, C; Bejarano, I; Dipierri, J; Alfaro, E; García, T

    2000-01-01

    Chagas disease constitutes the main zoonosis in the province of Jujuy, Argentina, where it is one of the most important issues in public health. The purpose of this paper is to analyze the results of a serologic evaluation carried out for a seven-year period among schoolchildren in the Jujenean capital city. The population under study consisted of all seventh grade students of all schools in San Salvador de Jujuy. They were classified into three socioeconomic levels: High, Medium and Low levels. Indirect hemagglutination and immunofluorescence tests were performed. Percentages of seroprevalence were determined by sex, age group, and socioeconomic level. To analyze and check results, the following tests were applied: ANOVA, Tukey's and chi-square test. General prevalence was 1.95% with inter-annual statistically non-significant variations. Statistically significant variations were found among: 1) sex, where the feminine sex exhibited higher seroprevalence; 2) age groups, in which 12-year-olds showed higher seroprevalence; 3) socioeconomic levels, where seroprevalence increased as socioeconomic level decreased. Chagasic seroprevalence in children populations is an indicator that allows assessing both transmission risks in the community and the efficiency of preventive measures to control the vector. Data resulting from this study would indicate: 1) an adequate control both of non-vectorial transmission as well as of the vector, since no temporal variation was recorded in seroprevalence in the age-group analyzed; 2) higher seroprevalence in children belonging to a lower socioeconomic level, probably due to migrations of already-infected mothers coming from neighboring endemic, less epidemiologically controlled areas.

  7. Interrupting Chagas disease transmission in Venezuela.

    PubMed

    Aché, A; Matos, A J

    2001-01-01

    The interruption of vectorial transmission of Chagas disease in Venezuela is attributed to the combined effects of ongoing entomoepidemiological surveillance, ongoing house spraying with residual insecticides and the concurrent building and modification of rural houses in endemic areas during almost five decades. The original endemic areas which totaled 750,000 km(2), have been reduced to 365,000 km(2). During 1958-1968, initial entomological evaluations carried out showed that the house infestation index ranged between 60-80%, the house infection index at 8-11% and a house density index of 30-50 triatomine bugs per house. By 1990-98, these indexes were further reduced to 1.6-4.0%, 0.01-0.6% and 3-4 bugs per house respectively. The overall rural population seroprevalence has declined from 44.5% (95% C.I.: 43.4-45.3%) to 9.2% (95% C.I.: 9.0-9.4%) for successive grouped periods from 1958 to 1998. The annual blood donor prevalence is firmly established below 1%. The population at risk of infection has been estimated to be less than four million. Given that prevalence rates are stable and appropriate for public health programmes, consideration has been given to potential biases that may distort results such as: a) geographical differences in illness or longevity of patients; b) variations in levels of ascertainment; c) variations in diagnostic criteria; and d) variations in population structure, mainly due to appreciable population migration. The endemic areas with continuous transmission are now mainly confined to piedmonts, as well as patchy foci in higher mountainous ranges, where the exclusive vector is Rhodnius prolixus. There is also an unstable area, of which landscapes are made up of grasslands with scattered broad-leaved evergreen trees and costal plains, where transmission is very low and occasional outbreaks are reported.

  8. 49 CFR 390.203 - PRISM State registration/biennial updates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false PRISM State registration/biennial updates. 390.203... FEDERAL MOTOR CARRIER SAFETY REGULATIONS; GENERAL Unified Registration System § 390.203 PRISM State... the Performance and Registration Information Systems Management (PRISM) program (authorized under...

  9. 49 CFR 390.203 - PRISM State registration/biennial updates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false PRISM State registration/biennial updates. 390.203... FEDERAL MOTOR CARRIER SAFETY REGULATIONS; GENERAL Unified Registration System § 390.203 PRISM State... the Performance and Registration Information Systems Management (PRISM) program (authorized under...

  10. Budding Architects: Exploring the Designs of Pyramids and Prisms

    ERIC Educational Resources Information Center

    Leavy, Aisling; Hourigan, Mairéad

    2015-01-01

    The context of students as architects is used to examine the similarities and differences between prisms and pyramids. Leavy and Hourigan use the Van Hiele Model as a tool to support teachers to develop expectations for differentiating geometry in the classroom using practical examples.

  11. Bagolini glasses: do they affect the horizontal prism fusion amplitude?

    PubMed

    Schultinga, L; Burggraaf, F; Polling, J R; Gutter, M

    2013-06-01

    Bagolini striated glasses (BSG) can be used while performing the prism fusion amplitude to verify the maintenance of binocularity. The aim of this clinical study was to evaluate whether these glasses affect the prism fusion amplitude. Fifty-six subjects were examined at the Eye Care Clinic at the University of Applied Sciences Utrecht. The positive and negative prism fusion amplitudes were measured, incorporating the BSG at random, for both near and distance, with right and left eye fixating. Fifty-two normal subjects with a mean age of 21 years (range 17-28) were recruited. The median prism fusion amplitude at near was 10 BI to 33 BO with the BSG and 13 BI to 38 BO without (p < 0.001). At distance the median amplitude was 8 BI to 33 BO both with and without these glasses (p = 0.104). Although BSG are useful to verify whether binocularity is maintained, significantly smaller fusional ranges were obtained during measurements at near. In clinical terms, fusional ranges can vary significantly when using the BSG.

  12. The Pacific Oaks College's Prism Principles Professional Development Approach

    ERIC Educational Resources Information Center

    Beyer, Kalani

    2012-01-01

    In a struggling atmosphere for education, one college is optimistic about the future by offering school districts its PRISM Principles professional development as a means to ensure that "no child is left behind." Pacific Oaks College & Children's School is known for its premiere programs in early childhood education, human…

  13. Budding Architects: Exploring the Designs of Pyramids and Prisms

    ERIC Educational Resources Information Center

    Leavy, Aisling; Hourigan, Mairéad

    2015-01-01

    The context of students as architects is used to examine the similarities and differences between prisms and pyramids. Leavy and Hourigan use the Van Hiele Model as a tool to support teachers to develop expectations for differentiating geometry in the classroom using practical examples.

  14. Experience with basal area estimation by prisms in lodgepole pine.

    Treesearch

    James M. Trappe

    1957-01-01

    Estimation of basal area by prisms offers intriguing possibilities for reducing time and effort in making stand inventories. Increased inventory efficiency is a particular need in stands that are relatively low in value due to small stems, predominance of low value species or heavy defect. In the Pacific Northwest, lodgepole pine characteristically forms dense low-...

  15. Adaptation to Laterally Displacing Prisms in Anisometropic Amblyopia.

    PubMed

    Sklar, Jaime C; Goltz, Herbert C; Gane, Luke; Wong, Agnes M F

    2015-06-01

    Using visual feedback to modify sensorimotor output in response to changes in the external environment is essential for daily function. Prism adaptation is a well-established experimental paradigm to quantify sensorimotor adaptation; that is, how the sensorimotor system adapts to an optically-altered visuospatial environment. Amblyopia is a neurodevelopmental disorder characterized by spatiotemporal deficits in vision that impacts manual and oculomotor function. This study explored the effects of anisometropic amblyopia on prism adaptation. Eight participants with anisometropic amblyopia and 11 visually-normal adults, all right-handed, were tested. Participants pointed to visual targets and were presented with feedback of hand position near the terminus of limb movement in three blocks: baseline, adaptation, and deadaptation. Adaptation was induced by viewing with binocular 11.4° (20 prism diopter [PD]) left-shifting prisms. All tasks were performed during binocular viewing. Participants with anisometropic amblyopia required significantly more trials (i.e., increased time constant) to adapt to prismatic optical displacement than visually-normal controls. During the rapid error correction phase of adaptation, people with anisometropic amblyopia also exhibited greater variance in motor output than visually-normal controls. Amblyopia impacts on the ability to adapt the sensorimotor system to an optically-displaced visual environment. The increased time constant and greater variance in motor output during the rapid error correction phase of adaptation may indicate deficits in processing of visual information as a result of degraded spatiotemporal vision in amblyopia.

  16. A new processing technology and detection method for isosceles prism

    NASA Astrophysics Data System (ADS)

    Guo, Rui; Su, Ying; Chen, Chaoping; Zhang, Yunlong; Li, Wenting; Zhang, Feng; Xu, Zengqi; Liu, Xuanmin

    2016-10-01

    The optical parallelism is an important indicators of isosceles prism. However, it cannot be directly measured in the processing process, and it is measured when the small surface is coated with silver film, which results in low processing rate. By analyzing the principles of the first optical parallelism and the second optical parallelism, this paper provides a new processing and detection method for isosceles prism. The good verticality between the three working face for isosceles prism and a side face can ensure the second optical parallelism. The small difference of 67.5°can ensure the first optical parallelism. By changing the position of the incident light when testing, the number of reflections can be reduced from seven to three. The reflection principle deduces the formula: θII(7)=2.4θII(3) which to improve the machining accuracy and avoid the surface imperfections in detection. By using this process, precision and productivity can be effectively improved, the complexity of the process is reduced, and the qualification of isosceles prism has been improved.

  17. Generalized prism-array lenses for hard X-rays.

    PubMed

    Cederström, Björn; Ribbing, Carolina; Lundqvist, Mats

    2005-05-01

    A Fresnel-like X-ray lens can be constructed by a triangular array of identical prisms whose base corresponds to the 2pi-shift length. Each column of prisms is progressively shifted from the optical axis by an arbitrary fraction of the prism height. Similarly to the multi-prism lens, quasi-parabolic profiles are formed by a superposition of straight-line segments. The resulting projected lens profile is approximately linear with a Fresnel-lens pattern superimposed on it to provide the focusing. This geometry exhibits a significantly larger effective aperture than conventional parabolic refractive lenses. Prototype lenses were fabricated by deep reactive ion etching of silicon. These one-dimensionally focusing lenses were tested at a synchrotron beamline and provided focal line-widths down to 1.4 microm FWHM and an intensity gain of 39 at a photon energy of 13.4 keV. Fabrication imperfections gave rise to unwanted interference effects resulting in several intensity maxima in the focal plane. The presented design allows the focal length to be shortened without decreasing the feature size of the lens. Furthermore, this feature size does not limit the resolution as for real Fresnel optics.

  18. 2. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM SOUTH OF THE SPILLWAY; VIEW TO SOUTHWEST FROM ROUTE 146 EMBANKMENT. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  19. 3. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM NORTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM NORTH OF THE SPILLWAY; VIEW TO WEST FROM ROUTE 146 EMBANKMENT. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  20. Drum dispersion equation for Littrow-type prism spectrometers.

    PubMed

    Sidran, M; Stalzer, H J; Hauptman, M H

    1966-07-01

    A simple analytic procedure has been developed for calibrating the wavelength drum of a Littrow-type prism spectrometer. Only three measured drum readings are required to specify the drum calibration over a broad wavelength range (uv to ir) with an accuracy of the order of the instrumental accuracy. This procedure can be applied to different prism materials for which measurements of refractive index have been performed. It is based on an approximate expression, derived from geometrical optics, relating the drum reading D(lambda) to the calculated refractive index n(lambda): D= A - B(a(2) - n(2))((1/2)). The index n(lambda) is calculated from the appropriate parametric equation. The temperature for the n(lambda) values need not be exactly that of the prism temperature during measurements. This expression was investigated for wavelengths in the range 0.3 micro to 2.25 micro using a sodium chloride prism. Computed drum positions D agreed with measured drum positions to within experimental error. Unknown wavelengths were computed from their measured drum positions to within the accuracy of the measurements.

  1. 4. VIEW SOUTH SHOWING AQUEDUCT PRISM. NOTE 1920 TIMBER AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW SOUTH SHOWING AQUEDUCT PRISM. NOTE 1920 TIMBER AND CONCRETE FLOORING SYSTEM, POCKETS FOR VERTICAL POSTS AND BRIDGING, STEEL BRACES ADDED BY THE NATIONAL PARK SERVICE CIRCA 1962. - Chesapeake & Ohio Canal, Conococheague Creek Aqueduct, Milepost 99.80, Williamsport, Washington County, MD

  2. 3. VIEW SOUTH SHOWING AQUEDUCT PRISM. NOTE 1920 TIMBER AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW SOUTH SHOWING AQUEDUCT PRISM. NOTE 1920 TIMBER AND CONCRETE FLOORING SYSTEM, CUT STONE FACE OF PARAPET WALL, AND WROUGHT IRON BOLTS USED TO SECURE THE RUBBING RAIL. - Chesapeake & Ohio Canal, Conococheague Creek Aqueduct, Milepost 99.80, Williamsport, Washington County, MD

  3. 1. GENERAL VIEW, TOWPATH BERM (CENTER) AND CANAL PRISM (LEFT) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW, TOWPATH BERM (CENTER) AND CANAL PRISM (LEFT) SOUTH OF THE SPILLWAY; VIEW TO SOUTH. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  4. Portable Remote Imaging Spectrometer (PRISM): Laboratory and Field Calibration

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis; Van Gorp, Byron; Green, Robert O.; Eastwood, Michael; Boardman, Joseph; Richardson, Brandon S.; Rodriguez, Jose I.; Urquiza, Eugenio; Franklin, Brian D.; Gao, Bo-Cai

    2012-01-01

    We report the characteristics of the Portable Remote Imaging Spectrometer, an airborne sensor specifically designed for the challenges of coastal ocean research. PRISM has high signal to noise ratio and uniformity, as well as low polarization sensitivity. Acquisition of high quality data has been demonstrated with the first engineering flight.

  5. Synthesis and photocatalytic activity of porous bismuth oxychloride hexagonal prisms.

    PubMed

    Ding, Liyong; Chen, Huan; Wang, Qingqian; Zhou, Tengfei; Jiang, Qingqing; Yuan, Yuhong; Li, Jinlin; Hu, Juncheng

    2016-01-18

    Porous BiOCl hexagonal prisms have been successfully prepared through a simple solvothermal route. These novel BiOCl HPs with porous structures are assembled from nanoparticles and exhibit high activity and selectivity toward the photocatalytic aerobic oxidation of benzyl alcohol to benzaldehyde and degradation of methyl orange.

  6. The Portable Remote Imaging Spectrometer (PRISM) Coastal Ocean Sensor

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis; VanGorp, Byron E.; Green, Robert O.; Eastwppd, Michael; Wilson, Daniel W.; Richardson, Brandon; Dierssen, Heidi

    2012-01-01

    PRISM is an airborne pushbroom imaging spectrometer intended to address the needs of airborne coastal ocean science research. Its critical characteristics are high throughput and signal-to-noise ratio, high uniformity of response to reduce spectral artifacts, and low polarization sensitivity. We give a brief overview of the instrument and results from laboratory calibration measurements regarding the spatial, spectral, radiometric and polarization characteristics.

  7. Compact prisms for polarisation splitting of fibre laser beams

    SciTech Connect

    Davydov, B L; Yagodkin, D I

    2005-11-30

    Simple compact monoprisms for spatial splitting of polarised laser beams with relatively small diameters (no more than 1 mm) are considered. Prisms can be made of optically inactive CaCO{sub 3}, {alpha}-BaB{sub 2}O{sub 4} ({alpha}-BBO), LiIO{sub 3}, LiNbO{sub 3}, YVO{sub 4}, and TiO{sub 2} crystals known in polarisation optics. The exact solution of the Snell equation for the extraordinary wave reflected from a surface arbitrarily tilted to its wave vector is obtained. The analysis of variants of the solution allows the fabrication of prisms with any deviation angles of the extraordinary wave by preserving the propagation direction of the ordinary wave. Three variants of prisms are considered: with minimised dimensions, with the Brewster output of the extraordinary beam, and with the deviation of the extraordinary wave by 90{sup 0}. Calcite prisms with the deviation angles for the extraordinary beam {approx}19{sup 0} and 90{sup 0} are tested experimentally. (control of laser radiation parameters)

  8. Payloads with Resource-Efficient Integration for Science Missions (PRISM)

    NASA Astrophysics Data System (ADS)

    Emam, O.; FitzGeorge, T.; Whittaker, A.; Wishart, A.; Fowell, S.; Prochazka, M.; Bentley, R.; Cole, R.; Brown, P.; Carr, C.; Cupido, E.; Oddy, T.

    2009-05-01

    PRISM is a collaborative industry and academia project to demonstrate the practicality of a highly integrated payload processing architecture, in order to exploit improvements in spacecraft computer performance to reduce multi-instrument payload mass and power requirements. Integrated architectures also provide opportunities for a greater degree of autonomy and advanced target selection (e.g. inter-instrument triggering). The PRISM architecture has potential advantages for missions such as EJSM (Europa Jupiter System Mission) or Solar Orbiter. The key technology objectives of PRISM are application partitioning on a qualifiable operating system, supported by the software required for fault-tolerant centralised processing, and the development of an application development environment for writing and testing instrument control applications. A working demonstrator has been implemented on a LEON3 platform, with representative payload applications from an in-situ magnetometer and a remote sensing extreme ultra-violet imager, both proposed for Solar Orbiter. PRISM is supported by the UK Science and Technology Facilities Council (STFC).

  9. Prism adaptation for spatial neglect after stroke: translational practice gaps.

    PubMed

    Barrett, A M; Goedert, Kelly M; Basso, Julia C

    2012-10-01

    Spatial neglect increases hospital morbidity and costs in around 50% of the 795,000 people per year in the USA who survive stroke, and an urgent need exists to reduce the care burden of this condition. However, effective acute treatment for neglect has been elusive. In this article, we review 48 studies of a treatment of intense neuroscience interest: prism adaptation training. Due to its effects on spatial motor 'aiming', prism adaptation training may act to reduce neglect-related disability. However, research failed, first, to suggest methods to identify the 50-75% of patients who respond to treatment; second, to measure short-term and long-term outcomes in both mechanism-specific and functionally valid ways; third, to confirm treatment utility during the critical first 8 weeks poststroke; and last, to base treatment protocols on systematic dose-response data. Thus, considerable investment in prism adaptation research has not yet touched the fundamentals needed for clinical implementation. We suggest improved standards and better spatial motor models for further research, so as to clarify when, how and for whom prism adaptation should be applied.

  10. Prism adaptation for spatial neglect after stroke: translational practice gaps

    PubMed Central

    Barrett, A. M.; Goedert, Kelly M.; Basso, Julia C.

    2012-01-01

    Spatial neglect increases hospital morbidity and costs in around 50% of the 795,000 people per year in the USA who survive stroke, and an urgent need exists to reduce the care burden of this condition. However, effective acute treatment for neglect has been elusive. In this article, we review 48 studies of a treatment of intense neuroscience interest: prism adaptation training. Due to its effects on spatial motor ‘aiming’, prism adaptation training may act to reduce neglect-related disability. However, research failed, first, to suggest methods to identify the 50–75% of patients who respond to treatment; second, to measure short-term and long-term outcomes in both mechanism-specific and functionally valid ways; third, to confirm treatment utility during the critical first 8 weeks poststroke; and last, to base treatment protocols on systematic dose–response data. Thus, considerable investment in prism adaptation research has not yet touched the fundamentals needed for clinical implementation. We suggest improved standards and better spatial motor models for further research, so as to clarify when, how and for whom prism adaptation should be applied. PMID:22926312

  11. Development of chagas cardiac manifestations among Texas blood donors.

    PubMed

    Garcia, Melissa N; Murray, Kristy O; Hotez, Peter J; Rossmann, Susan N; Gorchakov, Rodion; Ontiveros, Alejandra; Woc-Colburn, Laila; Bottazzi, Maria Elena; Rhodes, Charles E; Ballantyne, Christie M; Aguilar, David

    2015-01-01

    Chagas disease, infection with the parasite Trypanosoma cruzi, has recently been identified as an important emerging parasitic disease in the United States. To describe the cardiac abnormalities in T. cruzi-positive blood donors in southeastern Texas, a pilot study of donors who had screened positive from 2007 to 2012 was performed. This one-time assessment included (1) a questionnaire to evaluate the source of infection, cardiac symptoms, and health co-morbidities; (2) electrocardiography; (3) echocardiography if electrocardiographic findings were abnormal; and (4) measurement of a high-sensitivity troponin T biomarker. Of those with confirmed infection, 41% (7 of 17) had electrocardiographic abnormalities consistent with Chagas cardiomyopathy. In addition, 36% (6 of 17) were suspected to be locally acquired cases. High-sensitivity troponin T serum levels increased with cardiac severity. In conclusion, cardiologists should consider Chagas disease in their differential diagnoses for patients who may have clinically compatible electrocardiographic changes or nonischemic cardiomyopathy, even if the patients have no histories of residing in Chagas-endemic countries. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. American Trypanosomiasis (Also Known as Chagas Disease) Treatment

    MedlinePlus

    ... Laboratory Diagnostic Assistance [DPDx] Parasites Home Treatment Language: English (US) Español (Spanish) Recommend on Facebook Tweet Share Compartir Treatment for Chagas disease is recommended for people diagnosed early in the course of infection (acute phase), congenital infection, and for ...

  13. Pathogenesis of Chagas' Disease: Parasite Persistence and Autoimmunity

    PubMed Central

    Teixeira, Antonio R. L.; Hecht, Mariana M.; Guimaro, Maria C.; Sousa, Alessandro O.; Nitz, Nadjar

    2011-01-01

    Summary: Acute Trypanosoma cruzi infections can be asymptomatic, but chronically infected individuals can die of Chagas' disease. The transfer of the parasite mitochondrial kinetoplast DNA (kDNA) minicircle to the genome of chagasic patients can explain the pathogenesis of the disease; in cases of Chagas' disease with evident cardiomyopathy, the kDNA minicircles integrate mainly into retrotransposons at several chromosomes, but the minicircles are also detected in coding regions of genes that regulate cell growth, differentiation, and immune responses. An accurate evaluation of the role played by the genotype alterations in the autoimmune rejection of self-tissues in Chagas' disease is achieved with the cross-kingdom chicken model system, which is refractory to T. cruzi infections. The inoculation of T. cruzi into embryonated eggs prior to incubation generates parasite-free chicks, which retain the kDNA minicircle sequence mainly in the macrochromosome coding genes. Crossbreeding transfers the kDNA mutations to the chicken progeny. The kDNA-mutated chickens develop severe cardiomyopathy in adult life and die of heart failure. The phenotyping of the lesions revealed that cytotoxic CD45, CD8+ γδ, and CD8α+ T lymphocytes carry out the rejection of the chicken heart. These results suggest that the inflammatory cardiomyopathy of Chagas' disease is a genetically driven autoimmune disease. PMID:21734249

  14. Chagas disease transmission in periurban communities of Arequipa, Peru.

    PubMed

    Bowman, Natalie M; Kawai, Vivian; Levy, Michael Z; Cornejo del Carpio, Juan Geny; Cabrera, Lilia; Delgado, F; Malaga, Francisco; Cordova Benzaquen, Eleazar; Pinedo, Viviana V; Steurer, Francis; Seitz, Amy E; Gilman, Robert H; Bern, Caryn

    2008-06-15

    Chagas disease, caused by Trypanosoma cruzi infection, is an urban problem in Arequipa, Peru, and the epidemiology of Chagas disease is likely to be quite different in this area, compared with in rural zones. We conducted a serosurvey of 1615 children <18 years old in periurban districts that included hillside shantytowns and slightly more affluent low-lying communities. In addition, 639 adult residents of 1 shantytown were surveyed to provide data across the age spectrum for this community. Of 1615 children, 75 (4.7%) were infected with Trypanosoma cruzi. Infection risk increased by 12% per year of age, and children living in hillside shantytowns were 2.5 times as likely to be infected as were those living in lower-lying communities. However, age-prevalence data from 1 shantytown demonstrated that adults were no more likely to be seropositive than were teenagers; the results of maximum likelihood modeling suggest that T. cruzi transmission began in this community <20 years ago. The problem of Chagas disease in periurban settings, such as those around Arequipa, must be addressed to achieve elimination of vector-borne T. cruzi transmission. Identification of infected children, vector-control efforts, and education to avoid modifiable risk factors are necessary to decrease the burden of Chagas disease.

  15. Experimental Vaccines against Chagas Disease: A Journey through History

    PubMed Central

    Rodríguez-Morales, Olivia; Monteón-Padilla, Víctor; Carrillo-Sánchez, Silvia C.; Rios-Castro, Martha; Martínez-Cruz, Mariana; Carabarin-Lima, Alejandro; Arce-Fonseca, Minerva

    2015-01-01

    Chagas disease, or American trypanosomiasis, which is caused by the protozoan parasite Trypanosoma cruzi, is primarily a vector disease endemic in 21 Latin American countries, including Mexico. Although many vector control programs have been implemented, T. cruzi has not been eradicated. The development of an anti-T. cruzi vaccine for prophylactic and therapeutic purposes may significantly contribute to the transmission control of Chagas disease. Immune protection against experimental infection with T. cruzi has been studied since the second decade of the last century, and many types of immunogens have been used subsequently, such as killed or attenuated parasites and new DNA vaccines. This primary prevention strategy appears feasible, effective, safe, and inexpensive, although problems remain. The objective of this review is to summarize the research efforts about the development of vaccines against Chagas disease worldwide. A thorough literature review was conducted by searching PubMed with the terms “Chagas disease” and “American trypanosomiasis” together with “vaccines” or “immunization”. In addition, reports and journals not cited in PubMed were identified. Publications in English, Spanish, and Portuguese were reviewed. PMID:26090490

  16. Proteomic profile of circulating immune complexes in chronic Chagas disease.

    PubMed

    Ohyama, K; Huy, N T; Yoshimi, H; Kishikawa, N; Nishizawa, J E; Roca, Y; Revollo Guzmán, R J; Velarde, F U G; Kuroda, N; Hirayama, K

    2016-10-01

    Immune complexes (ICs) are the direct and real-time products of humoral immune responses. The identification of constituent foreign or autoantigens within ICs might bring new insights into the pathology of infectious diseases. We applied immune complexome analysis of plasma to the study of Chagas disease caused by Trypanosoma cruzi. Twenty seropositive plasma samples including cardiac and/or megacolon determinate patients (n = 11) and indeterminate (n = 9) were analysed along with 10 seronegative individuals to characterize the antigens bound to circulating ICs. We identified 39 T. cruzi antigens and 114 human autoantigens specific to patients with Chagas. Among those antigens, two T. cruzi antigens (surface protease GP63, glucose-6-isomerase) and six human autoantigens (CD180 antigen, ceruloplasmin, fibrinogen beta chain, fibrinogen beta chain isoform 2 preprotein, isoform gamma-A of fibrinogen γ-chain, serum paraoxonase) were detected in more than 50% of the patients tested. Human isoform short of complement factor H-related protein 2 and trans-sialidase of T. cruzi were more frequently found in the indeterminate (5/9 for both) compared with in the determinate Chagas (0/11, P = 0·046 for human, 1/11, P = 0·0498 for T. cruzi). The immune complexome could illustrate the difference of immune status between clinical forms of chronic Chagas disease. © 2016 John Wiley & Sons Ltd.

  17. Chagas Parasite Detection in Blood Images Using AdaBoost

    PubMed Central

    Uc-Cetina, Víctor; Brito-Loeza, Carlos; Ruiz-Piña, Hugo

    2015-01-01

    The Chagas disease is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi. Visual detection of such parasite through microscopic inspection is a tedious and time-consuming task. In this paper, we provide an AdaBoost learning solution to the task of Chagas parasite detection in blood images. We give details of the algorithm and our experimental setup. With this method, we get 100% and 93.25% of sensitivity and specificity, respectively. A ROC comparison with the method most commonly used for the detection of malaria parasites based on support vector machines (SVM) is also provided. Our experimental work shows mainly two things: (1) Chagas parasites can be detected automatically using machine learning methods with high accuracy and (2) AdaBoost + SVM provides better overall detection performance than AdaBoost or SVMs alone. Such results are the best ones known so far for the problem of automatic detection of Chagas parasites through the use of machine learning, computer vision, and image processing methods. PMID:25861375

  18. Global economic burden of Chagas disease: a computational simulation model

    PubMed Central

    Lee, Bruce Y; Bacon, Kristina M; Bottazzi, Maria Elena; Hotez, Peter J

    2013-01-01

    Summary Background As Chagas disease continues to expand beyond tropical and subtropical zones, a growing need exists to better understand its resulting economic burden to help guide stakeholders such as policy makers, funders, and product developers. We developed a Markov simulation model to estimate the global and regional health and economic burden of Chagas disease from the societal perspective. Methods Our Markov model structure had a 1 year cycle length and consisted of five states: acute disease, indeterminate disease, cardiomyopathy with or without congestive heart failure, megaviscera, and death. Major model parameter inputs, including the annual probabilities of transitioning from one state to another, and present case estimates for Chagas disease came from various sources, including WHO and other epidemiological and disease-surveillance-based reports. We calculated annual and lifetime health-care costs and disability-adjusted life-years (DALYs) for individuals, countries, and regions. We used a discount rate of 3% to adjust all costs and DALYs to present-day values. Findings On average, an infected individual incurs US$474 in health-care costs and 0·51 DALYs annually. Over his or her lifetime, an infected individual accrues an average net present value of $3456 and 3·57 DALYs. Globally, the annual burden is $627·46 million in health-care costs and 806 170 DALYs. The global net present value of currently infected individuals is $24·73 billion in health-care costs and 29 385 250 DALYs. Conversion of this burden into costs results in annual per-person costs of $4660 and lifetime per-person costs of $27 684. Global costs are $7·19 billion per year and $188·80 billion per lifetime. More than 10% of these costs emanate from the USA and Canada, where Chagas disease has not been traditionally endemic. A substantial proportion of the burden emerges from lost productivity from cardiovascular disease-induced early mortality. Interpretation The economic burden

  19. Estimating the Burden of Chagas Disease in the United States

    PubMed Central

    Manne-Goehler, Jennifer; Umeh, Chukwuemeka A.; Montgomery, Susan P.; Wirtz, Veronika J.

    2016-01-01

    Background In recent years, there has been growing awareness of the significant burden of Chagas disease in the United States (US). However, epidemiological data on both prevalence and access to care for this disease are limited. The objective of this study is to provide an updated national estimate of Chagas disease prevalence, the first state-level estimates of cases of T. cruzi infection in the US and to analyze these estimates in the context of data on confirmed cases of infection in the US blood supply. Methods In this study, we calculated estimates of the state and national prevalence of Chagas disease. The number of residents originally from Chagas disease endemic countries were computed using data on Foreign-Born Hispanic populations from the American Community Survey, along with recent prevalence estimates for Chagas disease in Latin America from the World Health Organization that were published in 2006 and updated in 2015. We then describe the distribution of estimated cases in each state in relation to the number of infections identified in the donated blood supply per data from the AABB (formerly American Association of Blood Banks). Findings The results of this analysis offer an updated national estimate of 238,091 cases of T. cruzi infection in the United States as of 2012, using the same method as was used by Bern and Montgomery to estimate cases in 2005. This estimate indicates that there are 62,070 cases less than the most recent prior estimate, though it does not include undocumented immigrants who may account for as many as 109,000 additional cases. The state level results show that four states (California, Texas, Florida and New York) have over 10,000 cases and an additional seven states have over 5,000 cases. Moreover, since 2007, the AABB has reported 1,908 confirmed cases of T. cruzi infection identified through screening of blood donations. Conclusions This study demonstrates a substantial burden of Chagas disease in the US, with state

  20. Chagas disease: control, elimination and eradication. Is it possible?

    PubMed

    Coura, José Rodrigues

    2013-12-01

    From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i) enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA) to southern Argentina and Chile (42ºN 49ºS), (ii) anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi from wild animals or vectors or when the vectors and wild animals, especially marsupials, invade the human domicile and infect man, (iii) zoonosis-amphixenosis and exchanged infection between animals and humans by domestic vectors in endemic areas and (iv) zooanthroponosis, infection that is transmitted from man to animals, by means of domestic vectors, which is the rarest situation in areas endemic for Chagas disease. The characteristics of Chagas disease as an enzooty of wild animals and as an anthropozoonosis are seen most frequently in the Brazilian Amazon and in the Pan-Amazon region as a whole, where there are 33 species of six genera of wild animals: Marsupialia, Chiroptera, Rodentia, Edentata (Xenarthra), Carnivora and Primata and 27 species of triatomines, most of which infected with T. cruzi . These conditions place the resident populations of this area or its visitors - tourists, hunters, fishermen and especially the people whose livelihood involves plant extraction - at risk of being affected by Chagas disease. On the other hand, there has been an exponential increase in the acute cases of Chagas disease in that region through oral transmission of T. cruzi , causing outbreaks of the disease. In four seroepidemiological surveys that were carried out in areas of the microregion of the Negro River, state of Amazonas, in 1991, 1993, 1997 and 2010, we found large numbers of people who were serologically positive for T. cruzi infection. The majority of them and/or their relatives worked in piassava extraction and had come into contact with and were stung by wild

  1. Chagas disease: control, elimination and eradication. Is it possible?

    PubMed Central

    Coura, José Rodrigues

    2013-01-01

    From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i) enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA) to southern Argentina and Chile (42ºN 49ºS), (ii) anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi from wild animals or vectors or when the vectors and wild animals, especially marsupials, invade the human domicile and infect man, (iii) zoonosis-amphixenosis and exchanged infection between animals and humans by domestic vectors in endemic areas and (iv) zooanthroponosis, infection that is transmitted from man to animals, by means of domestic vectors, which is the rarest situation in areas endemic for Chagas disease. The characteristics of Chagas disease as an enzooty of wild animals and as an anthropozoonosis are seen most frequently in the Brazilian Amazon and in the Pan-Amazon region as a whole, where there are 33 species of six genera of wild animals: Marsupialia, Chiroptera, Rodentia, Edentata (Xenarthra), Carnivora and Primata and 27 species of triatomines, most of which infected with T. cruzi . These conditions place the resident populations of this area or its visitors - tourists, hunters, fishermen and especially the people whose livelihood involves plant extraction - at risk of being affected by Chagas disease. On the other hand, there has been an exponential increase in the acute cases of Chagas disease in that region through oral transmission of T. cruzi , causing outbreaks of the disease. In four seroepidemiological surveys that were carried out in areas of the microregion of the Negro River, state of Amazonas, in 1991, 1993, 1997 and 2010, we found large numbers of people who were serologically positive for T. cruzi infection. The majority of them and/or their relatives worked in piassava extraction and had come into contact with and were stung by wild

  2. Estimating the Burden of Chagas Disease in the United States.

    PubMed

    Manne-Goehler, Jennifer; Umeh, Chukwuemeka A; Montgomery, Susan P; Wirtz, Veronika J

    2016-11-01

    In recent years, there has been growing awareness of the significant burden of Chagas disease in the United States (US). However, epidemiological data on both prevalence and access to care for this disease are limited. The objective of this study is to provide an updated national estimate of Chagas disease prevalence, the first state-level estimates of cases of T. cruzi infection in the US and to analyze these estimates in the context of data on confirmed cases of infection in the US blood supply. In this study, we calculated estimates of the state and national prevalence of Chagas disease. The number of residents originally from Chagas disease endemic countries were computed using data on Foreign-Born Hispanic populations from the American Community Survey, along with recent prevalence estimates for Chagas disease in Latin America from the World Health Organization that were published in 2006 and updated in 2015. We then describe the distribution of estimated cases in each state in relation to the number of infections identified in the donated blood supply per data from the AABB (formerly American Association of Blood Banks). The results of this analysis offer an updated national estimate of 238,091 cases of T. cruzi infection in the United States as of 2012, using the same method as was used by Bern and Montgomery to estimate cases in 2005. This estimate indicates that there are 62,070 cases less than the most recent prior estimate, though it does not include undocumented immigrants who may account for as many as 109,000 additional cases. The state level results show that four states (California, Texas, Florida and New York) have over 10,000 cases and an additional seven states have over 5,000 cases. Moreover, since 2007, the AABB has reported 1,908 confirmed cases of T. cruzi infection identified through screening of blood donations. This study demonstrates a substantial burden of Chagas disease in the US, with state variation that reflects the distribution of

  3. Superconducting magnetic Wollaston prism for neutron spin encoding.

    PubMed

    Li, F; Parnell, S R; Hamilton, W A; Maranville, B B; Wang, T; Semerad, R; Baxter, D V; Cremer, J T; Pynn, R

    2014-05-01

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ~30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ~98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

  4. Study of dose calculation on breast brachytherapy using prism TPS

    SciTech Connect

    Fendriani, Yoza; Haryanto, Freddy

    2015-09-30

    PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm{sup 3}. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm{sup 3}. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy.

  5. Superconducting magnetic Wollaston prism for neutron spin encoding

    NASA Astrophysics Data System (ADS)

    Li, F.; Parnell, S. R.; Hamilton, W. A.; Maranville, B. B.; Wang, T.; Semerad, R.; Baxter, D. V.; Cremer, J. T.; Pynn, R.

    2014-05-01

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ˜30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ˜98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

  6. Superconducting magnetic Wollaston prism for neutron spin encoding

    SciTech Connect

    Li, F. Parnell, S. R.; Wang, T.; Baxter, D. V.; Hamilton, W. A.; Maranville, B. B.; Semerad, R.; Cremer, J. T.; Pynn, R.

    2014-05-15

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ∼30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ∼98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

  7. Success of prisms in the management of diplopia due to fourth nerve palsy.

    PubMed

    Tamhankar, Madhura A; Ying, Gui-Shuang; Volpe, Nicholas J

    2011-09-01

    To analyze the success of prism use in alleviating diplopia in patients with fourth nerve palsy and to provide recommendations for prism prescription. In this retrospective cohort study, the medical records of 83 patients who were prescribed prisms for symptomatic diplopia due to fourth nerve palsy were analyzed. Data on the nature and duration of diplopia, motility and alignment findings, and amount and type of prism prescribed were recorded. The success of prescribed prismatic correction was assessed by the patient's self-reporting of satisfaction with prism use and follow-up records. The main outcome measure was the satisfaction rate associated with the use of prisms (satisfaction score 1 or 2) in patients with fourth nerve palsy. There were 69 patients with congenital fourth nerve palsy and 14 patients with acquired fourth nerve palsy who received prisms. The mean primary position (± SD) deviation in this group was 7.8 (± 4.6) prism diopters (PD). The mean prism prescription was 6 (± 2.9) PD. Overall, 92% of patients were satisfied with the use of prisms. During the length of follow-up, which ranged from 2 months to more than 6 years (median: 18 months), 86% of the cohort continued using prisms while 14% of patients underwent strabismus surgery. Among 15 patients who had primary position deviation greater than 15 PD, 80% of the patients reported satisfaction with prisms, and in the 11 patients who received 10 PD or more of prismatic correction, 82% were satisfied. Prisms are an effective modality for the management of patients with symptomatic diplopia due to fourth nerve palsy. Even in patients with larger deviations including those who were prescribed greater than 10 PD of correction, the success rate of prisms in alleviating diplopia was high. Prisms should be considered as initial therapy in symptomatic patients with fourth nerve palsy.

  8. Success of Prisms in the Management of Diplopia Due to Fourth Nerve Palsy

    PubMed Central

    Tamhankar, Madhura A.; Ying, Gui-shuang; Volpe, Nicholas J.

    2014-01-01

    Background To analyze the success of prism use in alleviating diplopia in patients with fourth nerve palsy and to provide recommendations for prism prescription. Methods In this retrospective cohort study, the medical records of 83 patients who were prescribed prisms for symptomatic diplopia due to fourth nerve palsy were analyzed. Data on the nature and duration of diplopia, motility and alignment findings, and amount and type of prism prescribed were recorded. The success of prescribed prismatic correction was assessed by the patient’s self-reporting of satisfaction with prism use and follow-up records. The main outcome measure was the satisfaction rate associated with the use of prisms (satisfaction score 1 or 2) in patients with fourth nerve palsy. Results There were 69 patients with congenital fourth nerve palsy and 14 patients with acquired fourth nerve palsy who received prisms. The mean primary position (±SD) deviation in this group was 7.8 (±4.6) prism diopters (PD). The mean prism prescription was 6 (±2.9) PD. Overall, 92% of patients were satisfied with the use of prisms. During the length of follow-up, which ranged from 2 months to more than 6 years (median: 18 months), 86% of the cohort continued using prisms while 14% of patients underwent strabismus surgery. Among 15 patients who had primary position deviation greater than 15 PD, 80% of the patients reported satisfaction with prisms, and in the 11 patients who received 10 PD or more of prismatic correction, 82% were satisfied. Conclusion Prisms are an effective modality for the management of patients with symptomatic diplopia due to fourth nerve palsy. Even in patients with larger deviations including those who were prescribed greater than 10 PD of correction, the success rate of prisms in alleviating diplopia was high. Prisms should be considered as initial therapy in symptomatic patients with fourth nerve palsy. PMID:21378578

  9. Current drug therapy and pharmaceutical challenges for Chagas disease.

    PubMed

    Bermudez, José; Davies, Carolina; Simonazzi, Analía; Real, Juan Pablo; Palma, Santiago

    2016-04-01

    One of the most significant health problems in the American continent in terms of human health, and socioeconomic impact is Chagas disease, caused by the protozoan parasite Trypanosoma cruzi. Infection was originally transmitted by reduviid insects, congenitally from mother to fetus, and by oral ingestion in sylvatic/rural environments, but blood transfusions, organ transplants, laboratory accidents, and sharing of contaminated syringes also contribute to modern day transmission. Likewise, Chagas disease used to be endemic from Northern Mexico to Argentina, but migrations have earned it global. The parasite has a complex life cycle, infecting different species, and invading a variety of cells - including muscle and nerve cells of the heart and gastrointestinal tract - in the mammalian host. Human infection outcome is a potentially fatal cardiomyopathy, and gastrointestinal tract lesions. In absence of a vaccine, vector control and treatment of patients are the only tools to control the disease. Unfortunately, the only drugs now available for Chagas' disease, Nifurtimox and Benznidazole, are relatively toxic for adult patients, and require prolonged administration. Benznidazole is the first choice for Chagas disease treatment due to its lower side effects than Nifurtimox. However, different strategies are being sought to overcome Benznidazole's toxicity including shorter or intermittent administration schedules-either alone or in combination with other drugs. In addition, a long list of compounds has shown trypanocidal activity, ranging from natural products to specially designed molecules, re-purposing drugs commercialized to treat other maladies, and homeopathy. In the present review, we will briefly summarize the upturns of current treatment of Chagas disease, discuss the increment on research and scientific publications about this topic, and give an overview of the state-of-the-art research aiming to produce an alternative medication to treat T. cruzi infection.

  10. The burden of Chagas disease: estimates and challenges.

    PubMed

    Stanaway, Jeffrey D; Roth, Gregory

    2015-09-01

    Chagas disease, caused by infection with the protozoa Trypanosoma cruzi is transmitted most often by Triatominae insect vectors, but also through blood transfusion, organ transplant, and congenital transmission. Between 5 and 18 million people are currently infected and the infection is estimated to cause more than 10,000 deaths annually. The disease has 3 phases: acute, indeterminate, and chronic. The acute phase immediately follows infection. It is typically asymptomatic but produces fever and malaise in up to 5% of people. The indeterminate phase is asymptomatic. More than one-half of those infected will remain in this phase for life and never experience long-term sequelae. After a decade or more, 20% to 30% of people will experience chronic cardiovascular Chagas disease with sequelae including heart failure, arrhythmias, and thromboembolism. Another 15% to 20% will experience chronic digestive sequela including megaesophagus and megacolon. A complete accounting of the burden of Chagas disease requires estimating the prevalence of the infection, the prevalence of each of its sequelae among those with the infection, and the number of deaths attributable to the infection. Attempts to estimate Chagas disease prevalence are complicated by several challenges imposed by the disease's extreme spatial heterogeneity, quickly evolving temporal trends, the decades-long lag between infection and symptomatic disease, biased prevalence data, incomplete recognition of Chagas-attributable deaths, limited data on sequela, and a near total absence of data outside of endemic countries. Even though researchers have found methodological approaches to dealing with these challenges, there is a need for better data. Copyright © 2015 World Heart Federation (Geneva). Published by Elsevier B.V. All rights reserved.

  11. Chagas disease in a Texan horse with neurologic deficits.

    PubMed

    Bryan, Laura K; Hamer, Sarah A; Shaw, Sarah; Curtis-Robles, Rachel; Auckland, Lisa D; Hodo, Carolyn L; Chaffin, Keith; Rech, Raquel R

    2016-01-30

    A 10-year-old Quarter Horse gelding presented to the Texas A&M University Veterinary Teaching Hospital with a six month-history of ataxia and lameness in the hind limbs. The horse was treated presumptively for equine protozoal myeloencephalitis (EPM) based on clinical signs but was ultimately euthanized after its condition worsened. Gross lesions were limited to a small area of reddening in the gray matter of the thoracic spinal cord. Histologically, trypanosome amastigotes morphologically similar to Trypanosoma cruzi, the agent of Chagas disease in humans and dogs, were sporadically detected within segments of the thoracic spinal cord surrounded by mild lymphoplasmacytic inflammation. Ancillary testing for Sarcocystis neurona, Neospora spp., Toxoplasma gondii and Leishmania spp. was negative. Conventional and real time polymerase chain reaction (PCR) of affected paraffin embedded spinal cord were positive for T. cruzi, and sequencing of the amplified T. cruzi satellite DNA PCR fragment from the horse was homologous with various clones of T. cruzi in GenBank. While canine Chagas disease cases have been widely reported in southern Texas, this is the first report of clinical T. cruzi infection in an equid with demonstrable amastigotes in the spinal cord. In contrast to previous instances of Chagas disease in the central nervous system (CNS) of dogs and humans, no inflammation or T. cruzi amastigotes were detected in the heart of the horse. Based on clinical signs, there is a potential for misdiagnosis of Chagas disease with other infectious diseases that affect the equine CNS. T. cruzi should be considered as a differential diagnosis in horses with neurologic clinical signs and histologic evidence of meningomyelitis that originate in areas where Chagas disease is present. The prevalence of T. cruzi in horses and the role of equids in the parasite life cycle require further study. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Experimental static aerodynamics of a regular hexagonal prism in a low density hypervelocity flow

    NASA Technical Reports Server (NTRS)

    Guy, R. W.; Mueller, J. N.; Lee, L. P.

    1972-01-01

    A regular hexagonal prism, having a fineness ratio of 1.67, has been tested in a wind tunnel to determine its static aerodynamic characteristics in a low-density hypervelocity flow. The prism tested was a 1/4-scale model of the graphite heat shield which houses the radioactive fuel for the Viking spacecraft auxiliary power supply. The basic hexagonal prism was also modified to simulate a prism on which ablation of one of the six side flats had occurred. This modified hexagonal prism was tested to determine the effects on the aerodynamic characteristics of a shape change caused by ablation during a possible side-on stable reentry.

  13. Justice where justice is due: A posthumous Nobel Prize to Carlos Chagas (1879-1934), the discoverer of American Trypanosomiasis (Chagas' disease).

    PubMed

    Bestetti, Reinaldo B; Martins, Cláudia A; Cardinalli-Neto, Augusto

    2009-05-01

    Working in the Brazilian backland, Chagas described a new disease. He discovered the etiologic agent, the vector, the reservoir, the acute stage, the several clinical aspects of the chronic stage (particularly the heart disease), role of autoimmunity in its pathogenesis, and anticipated the social impact of the disease. Chagas was nominated to Nobel Prize twice: in 1913, and in 1921. In 1913, Richet won the prize because his work on anaphylaxis. In 1921, no one received the Nobel Prize. It is believed that detraction of Chagas' work at the National Academy of Medicine, made by jealousy, mediocrity, and political rivalries can be maculated the image of the scientist. Furthermore, misperception of Chagas' work may also have led the Nobel Committee not to award him. One-hundred years after the discovery, we can appreciate the greatness of the discovery of Carlos Chagas, never seem in the realm of biological research. Time to make justice, therefore, has finally come.

  14. Forward and inverse solutions for three-element Risley prism beam scanners.

    PubMed

    Li, Anhu; Liu, Xingsheng; Sun, Wansong

    2017-04-03

    Scan blind zone and control singularity are two adverse issues for the beam scanning performance in double-prism Risley systems. In this paper, a theoretical model which introduces a third prism is developed. The critical condition for a fully eliminated scan blind zone is determined through a geometric derivation, providing several useful formulae for three-Risley-prism system design. Moreover, inverse solutions for a three-prism system are established, based on the damped least-squares iterative refinement by a forward ray tracing method. It is shown that the efficiency of this iterative calculation of the inverse solutions can be greatly enhanced by a numerical differentiation method. In order to overcome the control singularity problem, the motion law of any one prism in a three-prism system needs to be conditioned, resulting in continuous and steady motion profiles for the other two prisms.

  15. Dobutamine Stress Echocardiography Safety in Chagas Disease Patients.

    PubMed

    Rassi, Daniela do Carmo; Vieira, Marcelo Luiz Campos; Furtado, Rogerio Gomes; Turco, Fabio de Paula; Melato, Luciano Henrique; Hotta, Viviane Tiemi; Nunes, Colandy Godoy de Oliveira; Rassi, Luiz; Rassi, Salvador

    2017-02-01

    A few decades ago, patients with Chagas disease were predominantly rural workers, with a low risk profile for obstructive coronary artery disease (CAD). As urbanization has increased, they became exposed to the same risk factors for CAD of uninfected individuals. Dobutamine stress echocardiography (DSE) has proven to be an important tool in CAD diagnosis. Despite being a potentially arrhythmogenic method, it is safe for coronary patients without Chagas disease. For Chagas disease patients, however, the indication of DSE in clinical practice is uncertain, because of the arrhythmogenic potential of that heart disease. To assess DSE safety in Chagas disease patients with clinical suspicion of CAD, as well as the incidence of arrhythmias and adverse events during the exam. Retrospective analysis of a database of patients referred for DSE from May/2012 to February/2015. This study assessed 205 consecutive patients with Chagas disease suspected of having CAD. All of them had their serology for Chagas disease confirmed. Their mean age was 64±10 years and most patients were females (65.4%). No patient had significant adverse events, such as acute myocardial infarction, ventricular fibrillation, asystole, stroke, cardiac rupture and death. Regarding arrhythmias, ventricular extrasystoles occurred in 48% of patients, and non-sustained ventricular tachycardia in 7.3%. DSE proved to be safe in this population of Chagas disease patients, in which no potentially life-threatening outcome was found. Até poucas décadas atrás, os pacientes chagásicos eram predominantemente trabalhadores rurais, com baixo perfil de risco para doença obstrutiva coronária. Com a crescente urbanização, passaram a ter os mesmos fatores de risco para doença aterosclerótica que indivíduos não infectados. O ecocardiograma sob estresse com dobutamina (EED) é uma importante ferramenta no diagnóstico de coronariopatia. É referido, porém, como um método potencialmente arritmogênico, mas

  16. The effect of compliant prisms on subduction zone earthquakes and tsunamis

    NASA Astrophysics Data System (ADS)

    Lotto, Gabriel C.; Dunham, Eric M.; Jeppson, Tamara N.; Tobin, Harold J.

    2017-01-01

    Earthquakes generate tsunamis by coseismically deforming the seafloor, and that deformation is largely controlled by the shallow rupture process. Therefore, in order to better understand how earthquakes generate tsunamis, one must consider the material structure and frictional properties of the shallowest part of the subduction zone, where ruptures often encounter compliant sedimentary prisms. Compliant prisms have been associated with enhanced shallow slip, seafloor deformation, and tsunami heights, particularly in the context of tsunami earthquakes. To rigorously quantify the role compliant prisms play in generating tsunamis, we perform a series of numerical simulations that directly couple dynamic rupture on a dipping thrust fault to the elastodynamic response of the Earth and the acoustic response of the ocean. Gravity is included in our simulations in the context of a linearized Eulerian description of the ocean, which allows us to model tsunami generation and propagation, including dispersion and related nonhydrostatic effects. Our simulations span a three-dimensional parameter space of prism size, prism compliance, and sub-prism friction - specifically, the rate-and-state parameter b - a that determines velocity-weakening or velocity-strengthening behavior. We find that compliant prisms generally slow rupture velocity and, for larger prisms, generate tsunamis more efficiently than subduction zones without prisms. In most but not all cases, larger, more compliant prisms cause greater amounts of shallow slip and larger tsunamis. Furthermore, shallow friction is also quite important in determining overall slip; increasing sub-prism b - a enhances slip everywhere along the fault. Counterintuitively, we find that in simulations with large prisms and velocity-strengthening friction at the base of the prism, increasing prism compliance reduces rather than enhances shallow slip and tsunami wave height.

  17. Considering Apical Scotomas, Confusion, and Diplopia When Prescribing Prisms for Homonymous Hemianopia.

    PubMed

    Apfelbaum, Henry L; Ross, Nicole C; Bowers, Alex R; Peli, Eli

    2013-05-01

    While prisms are commonly prescribed for homonymous hemianopia to extend or expand the visual field, they cause potentially troubling visual side effects, including nonveridical location of perceived images, diplopia, and visual confusion. In addition, the field behind a prism at its apex is lost to an apical scotoma equal in magnitude to the amount of prism shift. The perceptual consequences of apical scotomas and the other effects of various designs were examined to consider parameters and designs that can mitigate the impact of these effects. Various configurations of sector and peripheral prisms were analyzed, in various directions of gaze, and their visual effects were illustrated using simulated perimetry. A novel "percept" diagram was developed that yielded insights into the patient's view through the prisms. The predictions were verified perimetrically with patients. The diagrams distinguish between potentially beneficial field expansion via visual confusion and the pericentrally disturbing and useless effect of diplopia, and their relationship to prism power and gaze direction. They also illustrate the nonexpanding substitution of field segments of some popular prism designs. Yoked sector prisms have no effect at primary gaze or when gaze is directed toward the seeing hemifield, and they introduce pericentral field loss when gaze is shifted into them. When fitted unilaterally, sector prisms also have an effect only when the gaze is directed into the prism and may cause a pericentral scotoma and/or central diplopia. Peripheral prisms are effective at essentially all gaze angles. Since gaze is not directed into them, they avoid problematic pericentral effects. We derive useful recommendations for prism power and position parameters, including novel ways of fitting prisms asymmetrically. Clinicians will find these novel diagrams, diagramming techniques, and analyses valuable when prescribing prismatic aids for hemianopia and when designing new prism devices

  18. Considering Apical Scotomas, Confusion, and Diplopia When Prescribing Prisms for Homonymous Hemianopia

    PubMed Central

    Apfelbaum, Henry L.; Ross, Nicole C.; Bowers, Alex R.; Peli, Eli

    2013-01-01

    Purpose: While prisms are commonly prescribed for homonymous hemianopia to extend or expand the visual field, they cause potentially troubling visual side effects, including nonveridical location of perceived images, diplopia, and visual confusion. In addition, the field behind a prism at its apex is lost to an apical scotoma equal in magnitude to the amount of prism shift. The perceptual consequences of apical scotomas and the other effects of various designs were examined to consider parameters and designs that can mitigate the impact of these effects. Methods: Various configurations of sector and peripheral prisms were analyzed, in various directions of gaze, and their visual effects were illustrated using simulated perimetry. A novel “percept” diagram was developed that yielded insights into the patient's view through the prisms. The predictions were verified perimetrically with patients. Results: The diagrams distinguish between potentially beneficial field expansion via visual confusion and the pericentrally disturbing and useless effect of diplopia, and their relationship to prism power and gaze direction. They also illustrate the nonexpanding substitution of field segments of some popular prism designs. Conclusions: Yoked sector prisms have no effect at primary gaze or when gaze is directed toward the seeing hemifield, and they introduce pericentral field loss when gaze is shifted into them. When fitted unilaterally, sector prisms also have an effect only when the gaze is directed into the prism and may cause a pericentral scotoma and/or central diplopia. Peripheral prisms are effective at essentially all gaze angles. Since gaze is not directed into them, they avoid problematic pericentral effects. We derive useful recommendations for prism power and position parameters, including novel ways of fitting prisms asymmetrically. Translational Relevance: Clinicians will find these novel diagrams, diagramming techniques, and analyses valuable when prescribing

  19. Chagas Disease, Migration and Community Settlement Patterns in Arequipa, Peru

    PubMed Central

    Gilman, Robert H.; Cornejo del Carpio, Juan G.; Naquira, Cesar; Bern, Caryn; Levy, Michael Z.

    2009-01-01

    Background Chagas disease is one of the most important neglected tropical diseases in the Americas. Vectorborne transmission of Chagas disease has been historically rare in urban settings. However, in marginal communities near the city of Arequipa, Peru, urban transmission cycles have become established. We examined the history of migration and settlement patterns in these communities, and their connections to Chagas disease transmission. Methodology/Principal Findings This was a qualitative study that employed focus group discussions and in-depth interviews. Five focus groups and 50 in-depth interviews were carried out with 94 community members from three shantytowns and two traditional towns near Arequipa, Peru. Focus groups utilized participatory methodologies to explore the community's mobility patterns and the historical and current presence of triatomine vectors. In-depth interviews based on event history calendars explored participants' migration patterns and experience with Chagas disease and vectors. Focus group data were analyzed using participatory analysis methodologies, and interview data were coded and analyzed using a grounded theory approach. Entomologic data were provided by an ongoing vector control campaign. We found that migrants to shantytowns in Arequipa were unlikely to have brought triatomines to the city upon arrival. Frequent seasonal moves, however, took shantytown residents to valleys surrounding Arequipa where vectors are prevalent. In addition, the pattern of settlement of shantytowns and the practice of raising domestic animals by residents creates a favorable environment for vector proliferation and dispersal. Finally, we uncovered a phenomenon of population loss and replacement by low-income migrants in one traditional town, which created the human settlement pattern of a new shantytown within this traditional community. Conclusions/Significance The pattern of human migration is therefore an important underlying determinant of

  20. Planar prism spectrometer based on adiabatically connected waveguiding slabs

    NASA Astrophysics Data System (ADS)

    Civitci, F.; Hammer, M.; Hoekstra, H. J. W. M.

    2016-04-01

    The device principle of a prism-based on-chip spectrometer for TE polarization is introduced. The spectrometer exploits the modal dispersion in planar waveguides in a layout with slab regions having two different thicknesses of the guiding layer. The set-up uses parabolic mirrors, for the collimation of light of the input waveguide and focusing of the light to the receiver waveguides, which relies on total internal reflection at the interface between two such regions. These regions are connected adiabatically to prevent unwanted mode conversion and loss at the edges of the prism. The structure can be fabricated with two wet etching steps. The paper presents basic theory and a general approach for device optimization. The latter is illustrated with a numerical example assuming SiON technology.

  1. Dissecting slander and crying for justice: Carlos Chagas and the Nobel Prize of 1921.

    PubMed

    Bestetti, Reinaldo B; Cardinalli-Neto, Augusto

    2013-10-03

    Chagas disease was discovered by Carlos Chagas in 1909. Chagas worked at Oswaldo Cruz Institute, where the bases of experimental medicine were settled in Brazil, and that had no connection with the Faculty of Medicine of Rio de Janeiro. Chagas had several enemies at Oswaldo Cruz Institute mainly because of his election to Head of Service in 1910, and for the position of Oswaldo Cruz Directorship in 1917. Furthermore, Chagas gained enemies at Faculty of Medicine of Rio de Janeiro, which did not like to see the economical political autonomy of Oswaldo Cruz Institute. This allowed the Institute not only to perform top experimental research, but also to take the leadership of research in the country. Chagas was nominated to the Nobel Prize of 1921 in December, 1920. None was awarded the Nobel Prize in that year. He seems to have been evaluated by the Noble Committee of Karolinska Institute from March to May of 1921. At that time, his enemies were denying his discovery of Trypanosoma cruzi, a key point in Chagas' nomination by Karolinska Institute, and giving no epidemiological importance for the disease. By the same way, the obligation of small pox vaccination was tarnishing his public image. Having taken into account the epidemiologic importance of Chagas disease, the strong historical mistake in the process of Chagas evaluation, and the inequity behind all these facts, we insist on a posthumous Nobel Prize for the man who made the most complete medical-scientist discovery of all time.

  2. Physician Knowledge of Chagas Disease in Hispanic Immigrants Living in Appalachian Ohio.

    PubMed

    Amstutz-Szalay, Shelley

    2017-06-01

    Studies have indicated that US physicians may not consider Chagas disease when diagnosing immigrant patients from Chagas-endemic areas. The purpose of this study was to evaluate physician knowledge of Chagas disease in six Appalachian Ohio counties. Physician knowledge was assessed by self-administrated survey (n = 105). Over 80 % of physicians reported that their current knowledge of Chagas disease was limited or very limited, and 50 % reported never considering Chagas disease diagnosis for their at-risk patients. Nearly 70 % of physicians were unaware of the percentage of chronic Chagas patients that develop clinical disease, and 36 % could not correctly identify the disease course. In addition, over 30 % of physicians reported that no services were available within their practice to assist Spanish-speaking patients with limited English proficiency. A lack of physician awareness of Chagas disease, coupled with a lack of translation services, may create a barrier to care by decreasing the likelihood of identification of patients at risk for Chagas disease. The results of this study support the need for interventions to ensure proper diagnosis and treatment of Chagas disease in Hispanic immigrants in rural Appalachian Ohio.

  3. Stereovision Imaging in Smart Mobile Phone Using Add on Prisms

    NASA Astrophysics Data System (ADS)

    Bar-Magen Numhauser, Jonathan; Zalevsky, Zeev

    2014-03-01

    In this work we present the use of a prism-based add on component installed on top of a smart phone to achieve stereovision capabilities using iPhone mobile operating system. Through these components and the combination of the appropriate application programming interface and mathematical algorithms the obtained results will permit the analysis of possible enhancements for new uses to such system, in a variety of areas including medicine and communications.

  4. Prism-coupled light emission from tunnel junctions

    NASA Technical Reports Server (NTRS)

    Ushioda, S.; Rutledge, J. E.; Pierce, R. M.

    1985-01-01

    Completely p-polarized light emission has been observed from smooth Al-AlO(x)-Au tunnel junctions placed on a prism coupler. The angle and polarization dependence demonstrate unambiguously that the emitted light is radiated by the fast-mode surface plasmon polariton. The emission spectra suggest that the dominant process for the excitation of the fast mode is through conversion of the slow mode to the fast mode mediated by residual roughness on the junction surface.

  5. An Assessment of the Crossed Porro Prism Resonator

    DTIC Science & Technology

    1980-08-01

    utilise Nd:YAIG lasers. Weapons Systems Research Laboratory is studying laser designation systems and Advanced Engineering Laboratory has recently...performed a feasibility study of a laser rangefinder for the RAAF(ref.l). This report has been prepared in response to the requirements of the above...the laser, but rather to study the change of energy with respect to the mis-slignment of the porro prisms. The relative pulse energy was monitored by

  6. PRISM: Recovery of the primordial spectrum from Planck data

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Paykari, P.; Starck, J.-L.; Sureau, F.; Bobin, J.; Rassat, A.

    2014-11-01

    Aims: The primordial power spectrum describes the initial perturbations that seeded the large-scale structure we observe today. It provides an indirect probe of inflation or other structure-formation mechanisms. In this Letter, we recover the primordial power spectrum from the Planck PR1 dataset, using our recently published algorithm PRISM. Methods: PRISM is a sparsity-based inversion method that aims at recovering features in the primordial power spectrum from the empirical power spectrum of the cosmic microwave background (CMB). This ill-posed inverse problem is regularised using a sparsity prior on features in the primordial power spectrum in a wavelet dictionary. Although this non-parametric method does not assume a strong prior on the shape of the primordial power spectrum, it is able to recover both its general shape and localised features. As a results, this approach presents a reliable way of detecting deviations from the currently favoured scale-invariant spectrum. Results: We applied PRISM to 100 simulated Planck data to investigate its performance on Planck-like data. We then applied PRISM to the Planck PR1 power spectrum to recover the primordial power spectrum. We also tested the algorithm's ability to recover a small localised feature at k ~ 0.125 Mpc-1, which caused a large dip at ℓ ~ 1800 in the angular power spectrum. Conclusions: We find no significant departures from the fiducial Planck PR1 near scale-invariant primordial power spectrum with As = 2.215 × 10-9 and ns = 0.9624.

  7. Prism therapy and visual rehabilitation in homonymous visual field loss.

    PubMed

    O'Neill, Evelyn C; Connell, Paul P; O'Connor, Jeremy C; Brady, Janice; Reid, Irene; Logan, Patricia

    2011-02-01

    Homonymous visual field defects (HVFD) are common and frequently occur after cerebrovascular accidents. They significantly impair visual function and cause disability particularly with regard to visual exploration. The purpose of this study was to assess a novel interventional treatment of monocular prism therapy on visual functioning in patients with HVFD of varied etiology using vision targeted, health-related quality of life (QOL) questionnaires. Our secondary aim was to confirm monocular and binocular visual field expansion pre- and posttreatment. Twelve patients with acquired, documented HVFD were eligible to be included. All patients underwent specific vision-targeted, health-related QOL questionnaire and monocular and binocular Goldmann perimetry before commencing prism therapy. Patients were fitted with monocular prisms on the side of the HVFD with the base-in the direction of the field defect creating a peripheral optical exotropia and field expansion. After the treatment period, QOL questionnaires and perimetry were repeated. Twelve patients were included in the treatment group, 10 of whom were included in data analysis. Overall, there was significant improvement within multiple vision-related, QOL functioning parameters, specifically within the domains of general health (p < 0.01), general vision (p < 0.05), distance vision (p < 0.01), peripheral vision (p < 0.05), role difficulties (p < 0.05), dependency (p < 0.05), and social functioning (p < 0.05). Visual field expansion was shown when measured monocularly and binocularly during the study period in comparison with pretreatment baselines. Patients with HVFD demonstrate decreased QOL. Monocular sector prisms can improve the QOL and expand the visual field in these patients.

  8. Spatial Compression Impairs Prism Adaptation in Healthy Individuals

    PubMed Central

    Scriven, Rachel J.; Newport, Roger

    2013-01-01

    Neglect patients typically present with gross inattention to one side of space following damage to the contralateral hemisphere. While prism-adaptation (PA) is effective in ameliorating some neglect behaviors, the mechanisms involved and their relationship to neglect remain unclear. Recent studies have shown that conscious strategic control (SC) processes in PA may be impaired in neglect patients, who are also reported to show extraordinarily long aftereffects compared to healthy participants. Determining the underlying cause of these effects may be the key to understanding therapeutic benefits. Alternative accounts suggest that reduced SC might result from a failure to detect prism-induced reaching errors properly either because (a) the size of the error is underestimated in compressed visual space or (b) pathologically increased error-detection thresholds reduce the requirement for error correction. The purpose of this study was to model these two alternatives in healthy participants and to examine whether SC and subsequent aftereffects were abnormal compared to standard PA. Each participant completed three PA procedures within a MIRAGE mediated reality environment with direction errors recorded before, during and after adaptation. During PA, visual feedback of the reach could be compressed, perturbed by noise, or represented veridically. Compressed visual space significantly reduced SC and aftereffects compared to control and noise conditions. These results support recent observations in neglect patients, suggesting that a distortion of spatial representation may successfully model neglect and explain neglect performance while adapting to prisms. PMID:23675332

  9. Large-deviation achromatic Risley prisms pointing systems

    NASA Astrophysics Data System (ADS)

    Lacoursiere, Jean; Doucet, Michel; Curatu, Eugene O.; Savard, Maxime; Verreault, Sonia; Thibault, Simon; Chevrette, Paul C.; Ricard, Benoit

    2002-06-01

    As part of the Infrared Eye project, this article describes the design of large-deviation, achromatic Risley prisms scanning systems operating in the 0.5 - 0.92 and 8 - 9.5 μm spectral regions. Designing these systems is challenging due to the large deviation required (zero - 25 degrees), the large spectral bandwidth and the mechanical constraints imposed by the need to rotate the prisms to any position in 1/30 second. A design approach making extensive use of the versatility of optical design softwares is described. Designs consisting of different pairs of optical materials are shown in order to illustrate the trade-off between chromatic aberration, mass and vignetting. Control of chromatic aberration and reasonable prism shape is obtained over 8 - 9.5 μm with zinc sulfide and germanium. The design is more difficult for the 0.5 - 0.92 μm band. Trade-offs consist in using sapphire with Cleartran« over a reduced bandwidth (0.75 - 0.9 μm ) or acrylic singlets with the Infrared Eye in active mode (0.85 - 0.86 μm). Non-sequential ray-tracing is used to study the effects of fresnelizing one element of the achromat to reduce its mass, and to evaluate detector narcissus in the 8 - 9.5 μm region.

  10. PRISM Triplet and Stereopairs to Build Digital Surface Models

    NASA Astrophysics Data System (ADS)

    Baiocchi, Valerio; Milone, Maria Vittoria; Mormile, Martina

    2012-04-01

    In the present paper the phases of extraction of a DSM from Prism stereopairs and triplets are illustrated. PRISM was a panchromatic radiometer carried onboard the Japanese remote sensing satellite ALOS (Advanced Land Observing Satellite); this work has mainly a methodological value cause on May 12, 2011, a command was sent to stop the onboard transmitter and now the sensor is no more operative. The sensor had three optical systems for forward, nadir and backward views with 2.5 meter nominal spatial resolution. Multiple Linear Array CCD chips were located on the focal plane of each camera, along one across-track line. Images here studied represent a coastal area that spans from the city of Pescara to the city of Ortona (both in Abruzzo region, Italy). The availability of PRISM stereopairs and triplets is not widely studied and in this paper accuracy of produced DEMs is compared with heights from terrestrial Lidar survey on the area of the city of Pescara (Abruzzo region, Italy). Extraction was executed with Geomatica 2012 using rigorous model, with GCPs.

  11. Controllable Sonar Lenses and Prisms Based on ERFs

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Sherrit, Stewart; Chang, Zensheu; Bao, Xiaoqi; Paustian, Iris; Lopes, Joseph; Folds, Donald

    2004-01-01

    Sonar-beam-steering devices of the proposed type would contain no moving parts and would be considerably smaller and less power-hungry, relative to conventional multiple-beam sonar arrays. The proposed devices are under consideration for installation on future small autonomous underwater vehicles because the sizes and power demands of conventional multiple-beam arrays are excessive, and motors used in single-beam mechanically scanned systems are also not reliable. The proposed devices would include a variety of electrically controllable acoustic prisms, lenses, and prism/lens combinations both simple and compound. These devices would contain electrorheological fluids (ERFs) between electrodes. An ERF typically consists of dielectric particles floating in a dielectric fluid. When an electric field is applied to the fluid, the particles become grouped into fibrils aligned in rows, with a consequent increase in the viscosity of the fluid and a corresponding increase in the speed of sound in the fluid. The change in the speed of sound increases with an increase in the applied electric field. By thus varying the speed of sound, one varies the acoustic index of refraction, analogously to varying the index of refraction of an optical lens or prism. In the proposed acoustic devices, this effect would be exploited to control the angles of refraction of acoustic beams, thereby steering the beams and, in the case of lenses, controlling focal lengths.

  12. Comparison of thermal modeling, microstructural analysis, and Ti-in-quartz thermobarometry to constrain the thermal history of a cooling pluton during deformation in the Mount Abbot Quadrangle, CA

    NASA Astrophysics Data System (ADS)

    Nevitt, Johanna M.; Warren, Jessica M.; Kidder, Steven; Pollard, David D.

    2017-03-01

    Granitic plutons commonly preserve evidence for jointing, faulting, and ductile fabric development during cooling. Constraining the spatial variation and temporal evolution of temperature during this deformation could facilitate an integrated analysis of heterogeneous deformation over multiple length-scales through time. Here, we constrain the evolving temperature of the Lake Edison granodiorite within the Mount Abbot Quadrangle (central Sierra Nevada, CA) during late Cretaceous deformation by combining microstructural analysis, titanium-in-quartz thermobarometry (TitaniQ), and thermal modeling. Microstructural and TitaniQ analyses were applied to 12 samples collected throughout the pluton, representative of either the penetrative "regional" fabric or the locally strong "fault-related" fabric. Overprinting textures and mineral assemblages indicate the temperature decreased from 400-500°C to <350°C during faulting. TitaniQ reveals consistently lower Ti concentrations for partially reset fault-related fabrics (average: 12 ± 4 ppm) than for regional fabrics (average: 31 ± 12 ppm), suggesting fault-related fabrics developed later, following a period of pluton cooling. Uncertainties, particularly in TiO2 activity, significantly limit further quantitative thermal estimates using TitaniQ. In addition, we present a 1-D heat conduction model that suggests average pluton temperature decreased from 585°C at 85 Ma to 332°C at 79 Ma, consistent with radiometric age data for the field. Integrated with the model results, microstructural temperature constraints suggest faulting initiated by ˜83 Ma, when the temperature was nearly uniform across the pluton. Thus, spatially heterogeneous deformation cannot be attributed to a persistent temperature gradient, but may be related to regional structures that develop in cooling plutons.

  13. Motor unit involvement in human acute Chagas' disease.

    PubMed

    Benavente, O R; Patiño, O L; Peña, L B; Lugònes, H; Kalala, E; Meneclier, C R; Genovese, O; Sica, R E

    1989-09-01

    Thirty five patients with acute Chagas' disease who demonstrated parasitaemia at the time of the investigation were submitted to a detailed electromyographical study. With their muscles at rest, 12 patients showed fibrillation potentials and/or positive sharp waves. On volitional contraction, 7 had short duration motor unit potentials (MUPs) and low polyphasic MUPs. On motor and sensory nerve fibers conduction studies, 20 disclosed values below the lower control limit within one or more nerves. Finally, 12 patients produced a muscle decremental response on nerve supramaximal repetitive stimulation. The findings signal that primary muscle involvement, neuropathy and impairement of the neuromuscular transmission, either isolated or combined, may be found in the acute stage of human Chagas' disease.

  14. Neglected Parasitic Infections in the United States: Chagas Disease

    PubMed Central

    Montgomery, Susan P.; Starr, Michelle C.; Cantey, Paul T.; Edwards, Morven S.; Meymandi, Sheba K.

    2014-01-01

    Chagas disease, which is caused by the protozoan parasite Trypanosoma cruzi, can lead to severe cardiac and gastrointestinal disease. Most persons acquire this infection through contact with vector bugs carrying T. cruzi in endemic areas of Latin America. Infection can also be acquired by congenital, transfusion, transplantation, and foodborne transmission. Although an estimated 300,000 persons with Chagas disease live in the United States, little is known about the burden of chagasic heart disease. It is not known how often congenital or vector-borne transmission of T. cruzi occurs in the United States, although it is known that infected mothers and infected vector bugs are found in this country. Better diagnostic tests and treatment drugs are needed to improve patient care, and research is needed to define transmission risks and develop strategies to prevent new infections and reduce the burden of disease. PMID:24808250

  15. Therapy of Chagas Disease: Implications for Levels of Prevention

    PubMed Central

    Sosa-Estani, Sergio; Colantonio, Lisandro; Segura, Elsa Leonor

    2012-01-01

    This paper reviews the evidence supporting the use of etiological treatment for Chagas disease that has changed the standard of care for patients with Trypanosoma cruzi infection in the last decades. Implications of this evidence on different levels of prevention as well as gaps in current knowledge are also discussed. In this regard, etiological treatment has shown to be beneficial as an intervention for secondary prevention to successfully cure the infection or to delay, reduce, or prevent the progression to disease, and as primary disease prevention by breaking the chain of transmission. Timely diagnosis during initial stages would allow for the prescription of appropriate therapies mainly in the primary health care system thus improving chances for a better quality of life. Based on current evidence, etiological treatment has to be considered as an essential public health strategy useful to reduce disease burden and to eliminate Chagas disease altogether. PMID:22523499

  16. Comparison of the visual effects of Fresnel prisms in normal and amblyopic eyes.

    PubMed

    Wright, David; Firth, Alison Y; Buckley, David

    2008-10-01

    To assess the effects of Fresnel prisms on visual acuity and peak contrast sensitivity in the amblyopic and sound eyes of participants with amblyopia and to determine whether these functions were affected by Fresnel prisms to a different degree than those of controls. The LogMAR visual acuity and peak contrast sensitivity of 10 unilateral amblyopic participants (mean age, 22.6 years) and 9 controls (mean age, 26.2 years) were tested with Fresnel prisms of powers 5(Delta), 10(Delta), 15(Delta), 20(Delta), and 25(Delta) and without a Fresnel prism. A statistically significant reduction in visual acuity with increasing prism power was found for all 3 groups, with the visual acuity of the amblyopic eyes being the least affected by the prisms. No statistically significant differences were found between the control and the sound eyes. No statistically significant differences in the effects of the prisms on peak contrast sensitivity could be detected between the 3 groups. Fresnel prisms were found to have a smaller effect on those amblyopic eyes with a poorer baseline visual acuity, indicating that these eyes may tolerate strong prisms without substantially impairing their visual acuity. Fresnel prisms have a lesser effect on the visual acuity of amblyopic eyes than on controls. In contrast, results for peak contrast sensitivity were very similar for each of the groups tested, and no significant differences were evident between the amblyopic, sound, and control eyes.

  17. Stabilization of a self-referenced, prism-based, Cr:forsterite laser frequency comb using an intracavity prism

    SciTech Connect

    Tillman, Karl A.; Thapa, Rajesh; Knabe, Kevin; Wu Shun; Lim, Jinkang; Washburn, Brian R.; Corwin, Kristan L.

    2009-12-20

    The frequency comb from a prism-based Cr:forsterite laser has been frequency stabilized using intracavity prism insertion and pump power modulation. Absolute frequency measurements of a CW fiber laser stabilized to the P(13) transition of acetylene demonstrate a fractional instability of {approx}2x10{sup -11} at a 1 s gate time, limited by a commercial Global Positioning System (GPS)-disciplined rubidium oscillator. Additionally, absolute frequency measurements made simultaneously using a second frequency comb indicate relative instabilities of 3x10{sup -12} for both combs for a 1 s gate time. Estimations of the carrier-envelope offset frequency linewidth based on relative intensity noise and the response dynamics of the carrier-envelope offset to pump power changes confirm the observed linewidths.

  18. Current situation and perspectives regarding human Chagas disease in midwestern of the state of Minas Gerais, Brazil

    PubMed Central

    Matos, Christiane Santos; dos Santos, José Eloy; Medeiros, Fernanda Alvarenga Cardoso; Furtado, Eliana; Dias, João Carlos Pinto

    2014-01-01

    Recognising the importance of Chagas disease in Brazil, Bambuí set up epidemiological surveillance for Chagas disease in 1974 and was the first municipality to do so. To ascertain the current epidemiology of Chagas disease in this municipality, 1.782 blood samples from the general population were analysed; 7.7% of samples were found to be seropositive for Chagas disease. A strong positive correlation between increasing age and Chagas disease was evident in both genders, with the highest prevalence in individuals aged over 60 years. Clinically, the cardiodigestive form of Chagas disease was the most common in these samples. These data confirm the interruption of Trypanosoma cruzi transmission, in parallel with a still important residual morbidity of Chagas disease in the county, thus supporting political decisions that will prioritise epidemiological surveillance and medical treatment of Chagas disease in the coming years. PMID:24831551

  19. Economic evaluation of Chagas disease screening in Spain.

    PubMed

    Imaz-Iglesia, Iñaki; Miguel, Lucía García-San; Ayala-Morillas, L Eduardo; García-Pérez, Lidia; González-Enríquez, Jesús; Blasco-Hernández, Teresa; Martín-Águeda, María Belén; Sarría-Santamera, Antonio

    2015-08-01

    Although Spain is the European country with the highest Chagas disease burden, the country does not have a national control program of the disease. The purpose of this study is to evaluate the efficiency of several strategies for Chagas disease screening among Latin American residents living in Spain. The following screening strategies were evaluated: (1) non-screening; (2) screening of the Latin American pregnant women and their newborns; (3) screening also the relatives of the positive pregnant women; (4) screening also the relatives of the negative pregnant women. A cost-utility analysis was carried out to compare the four strategies from two perspectives, the societal and the Spanish National Health System (SNHS). A decision tree representing the clinical evolution of Chagas disease throughout patient's life was built. The strategies were compared through the incremental cost-utility ratio, using euros as cost measurement and quality-adjusted life years as utility measurement. A sensitivity analysis was performed to test the model parameters and their influence on the results. We found the "Non-screening" as the most expensive and less effective of the evaluated strategies, from both the societal and the SNHS perspectives. Among the screening evaluated strategies the most efficient was, from both perspectives, to extent the antenatal screening of the Latin American pregnant women and their newborns up to the relatives of the positive women. Several parameters influenced significantly on the sensitivity analyses, particularly the chronic treatment efficacy or the prevalence of Chagas disease. In conclusion, for the general Latin American immigrants living in Spain the most efficient would be to screen the Latin American mothers, their newborns and the close relatives of the mothers with a positive serology. However for higher prevalence immigrant population the most efficient intervention would be to extend the program to the close relatives of the negative

  20. Challenges and perspectives of Chagas disease: a review

    PubMed Central

    2013-01-01

    Chagas disease (CD), also known as American trypanosomiasis, is caused by the flagellated protozoan Trypanosoma cruzi, and affects an estimated 8 to 10 million people worldwide. In Latin America, 25 million people live in risk areas, while in 2008 alone, 10,000 CD-related deaths were reported. This review aimed to evaluate the challenges of CD control, future perspectives, and actions performed worldwide to control expansion of the disease and its impact on public health in Latin America. PMID:24354455

  1. [Chagas' disease in Mexico. Report of 5 proven cases].

    PubMed

    Marcuchamer Miller, J; Reyes López, P A

    1978-01-01

    Seroepidemiologic studies demonstrated that American Trypanosomiasis is highly prevalent among rural communities in Mexico. However, Chagas' disease seems to be a rarity. That could be a wrong concept. In just a few months 5 patients with epidemiological, clinical and immunologic evidence for Chagasic miocardiopathy or miocarditis were identified in our Institution. Their cardiologic findings have been discussed, as well as diagnostic approaches in different stages of the disease.

  2. Chagas Cardiomyopathy in the Context of the Chronic Disease Transition

    PubMed Central

    Hidron, Alicia I.; Gilman, Robert H.; Justiniano, Juan; Blackstock, Anna J.; LaFuente, Carlos; Selum, Walter; Calderon, Martiza; Verastegui, Manuela; Ferrufino, Lisbeth; Valencia, Eduardo; Tornheim, Jeffrey A.; O'Neal, Seth; Comer, Robert; Galdos-Cardenas, Gerson; Bern, Caryn

    2010-01-01

    Background Patients with Chagas disease have migrated to cities, where obesity, hypertension and other cardiac risk factors are common. Methodology/Principal Findings The study included adult patients evaluated by the cardiology service in a public hospital in Santa Cruz, Bolivia. Data included risk factors for T. cruzi infection, medical history, physical examination, electrocardiogram, echocardiogram, and contact 9 months after initial data collection to ascertain mortality. Serology and PCR for Trypanosoma cruzi were performed. Of 394 participants, 251 (64%) had confirmed T. cruzi infection by serology. Among seropositive participants, 109 (43%) had positive results by conventional PCR; of these, 89 (82%) also had positive results by real time PCR. There was a high prevalence of hypertension (64%) and overweight (body mass index [BMI] >25; 67%), with no difference by T. cruzi infection status. Nearly 60% of symptomatic congestive heart failure was attributed to Chagas cardiomyopathy; mortality was also higher for seropositive than seronegative patients (p = 0.05). In multivariable models, longer residence in an endemic province, residence in a rural area and poor housing conditions were associated with T. cruzi infection. Male sex, increasing age and poor housing were independent predictors of Chagas cardiomyopathy severity. Males and participants with BMI ≤25 had significantly higher likelihood of positive PCR results compared to females or overweight participants. Conclusions Chagas cardiomyopathy remains an important cause of congestive heart failure in this hospital population, and should be evaluated in the context of the epidemiological transition that has increased risk of obesity, hypertension and chronic cardiovascular disease. PMID:20502520

  3. Prism: a new approach to radiotherapy planning software.

    PubMed

    Kalet, I J; Jacky, J P; Austin-Seymour, M M; Hummel, S M; Sullivan, K J; Unger, J M

    1996-09-01

    We describe the capabilities and performance of Prism, an innovative new radiotherapy planning system with unusual features and design. The design and implementation strategies are intended to assure high quality and clinical acceptability. The features include Artificial Intelligence tools and special support for multileaf collimator (MLC) systems. The design provides unusual flexibility of operation and ease of expansion. We have implemented Prism, a three-dimensional (3D) radiotherapy treatment-planning system on standard commercial workstations with the widely available X window system. The design and implementation use ideas taken from recent software engineering research, for example, the use of behavioral entity-relationship modeling and the "Mediator Method" instead of ad-hoc programming. The Prism system includes the usual features of a 3D planning system, including Beam's Eye View and the ability to simulate any treatment geometry possible with any standard radiotherapy accelerator. It includes a rule-based expert system for automated generation of the planning target volume as defined in ICRU Report 50. In addition, it provides special support for planning treatments with a multileaf collimator (MLC). We also implemented a Radiotherapy Treatment Planning Tools Foundation for Prism, so that we are able to use software tools form other institutions without any source code modification. The Prism system has been in clinical operation at the University of Washington since July 1994 and has been installed at several other clinics. The system is run simultaneously by several users, each with their own workstation operating from a common networked database and software. In addition to the dosimetrists, the system is used by radiation oncologists to define tumor and target volumes and by radiation therapists to select treatment setups to load into a computer controlled accelerator. Experience with the installation and operation has shown the design to be

  4. Prism adaptation contrasts perceptual habituation for repetitive somatosensory stimuli.

    PubMed

    Torta, D M; Tatu, M K; Cotroneo, D; Alamia, A; Folegatti, A; Trojan, J

    2016-03-01

    Prism adaptation (PA) is a non-invasive procedure that requires performing a visuo-motor pointing task while wearing prism goggles inducing a visual displacement of the pointed target. This procedure involves a reorganization of sensorimotor coordination, and induces long-lasting effects on numerous higher-order cognitive functions in healthy volunteers and neglect patients. Prismatic displacement (PD) of the visual field can be induced when prisms are worn but no sensorimotor task is required. In this case, it is unlikely that any subsequent reorganization takes place. The effects of PD are short-lived in the sense that they last as long as prisms are worn. In this study we aimed, to the best of our knowledge for the first time, at investigating whether PA and PD induce changes in the perception of intensity of nociceptive and non- nociceptive somatosensory stimuli. We induced, in healthy volunteers, PD (experiment 1), or PA (experiment 2) and asked participants to rate the intensity of the stimuli applied to the hand undergoing the visuo-proprioceptive conflict (experiment 1) or adaptation (experiment 2). Our results indicate that: 1) the visuo-proprioceptive conflict induced by PD does not reduce the perceived intensity of the stimuli, 2) PA prevents perceptual habituation for both nociceptive and non-nociceptive somatosensory stimuli. Moreover, to investigate the possible underlying mechanisms of the effects of PA we conducted a third experiment in which stimuli were applied both at the adapted and the non-adapted hand. In line with the results of experiment 2, we found that perceptual habituation was prevented for stimuli applied onto the adapted hand. Moreover, we observed the same finding for stimuli applied onto the non-adapted hand. This result suggests that the detention of habituation is not merely driven by changes in spatial attention allocation. Taken together, these data indicate that prisms can affect the perceived intensity of somatosensory stimuli

  5. Opportunity cost for early treatment of Chagas disease in Mexico.

    PubMed

    Ramsey, Janine M; Elizondo-Cano, Miguel; Sanchez-González, Gilberto; Peña-Nieves, Adriana; Figueroa-Lara, Alejandro

    2014-04-01

    Given current neglect for Chagas disease in public health programs in Mexico, future healthcare and economic development policies will need a more robust model to analyze costs and impacts of timely clinical attention of infected populations. A Markov decision model was constructed to simulate the natural history of a Chagas disease cohort in Mexico and to project the associated short and long-term clinical outcomes and corresponding costs. The lifetime cost for a timely diagnosed and treated Chagas disease patient is US$ 10,160, while the cost for an undiagnosed individual is US$ 11,877. The cost of a diagnosed and treated case increases 24-fold from early acute to indeterminate stage. The major cost component for lifetime cost was working days lost, between 44% and 75%, depending on the program scenario for timely diagnosis and treatment. In the long term, it is cheaper to diagnose and treat chagasic patients early, instead of doing nothing. This finding by itself argues for the need to shift current policy, in order to prioritize and attend this neglected disease for the benefit of social and economic development, which implies including treatment drugs in the national formularies. Present results are even more relevant, if one considers that timely diagnosis and treatment can arrest clinical progression and enhance a chronic patient's quality of life.

  6. Trypanosoma cruzi and Chagas' Disease in the United States.

    PubMed

    Bern, Caryn; Kjos, Sonia; Yabsley, Michael J; Montgomery, Susan P

    2011-10-01

    Chagas' disease is caused by the protozoan parasite Trypanosoma cruzi and causes potentially life-threatening disease of the heart and gastrointestinal tract. The southern half of the United States contains enzootic cycles of T. cruzi, involving 11 recognized triatomine vector species. The greatest vector diversity and density occur in the western United States, where woodrats are the most common reservoir; other rodents, raccoons, skunks, and coyotes are also infected with T. cruzi. In the eastern United States, the prevalence of T. cruzi is highest in raccoons, opossums, armadillos, and skunks. A total of 7 autochthonous vector-borne human infections have been reported in Texas, California, Tennessee, and Louisiana; many others are thought to go unrecognized. Nevertheless, most T. cruzi-infected individuals in the United States are immigrants from areas of endemicity in Latin America. Seven transfusion-associated and 6 organ donor-derived T. cruzi infections have been documented in the United States and Canada. As improved control of vector- and blood-borne T. cruzi transmission decreases the burden in countries where the disease is historically endemic and imported Chagas' disease is increasingly recognized outside Latin America, the United States can play an important role in addressing the altered epidemiology of Chagas' disease in the 21st century.

  7. Prophylactic and therapeutic DNA vaccines against Chagas disease.

    PubMed

    Arce-Fonseca, Minerva; Rios-Castro, Martha; Carrillo-Sánchez, Silvia del Carmen; Martínez-Cruz, Mariana; Rodríguez-Morales, Olivia

    2015-02-24

    Chagas disease is a zoonosis caused by Trypanosoma cruzi in which the most affected organ is the heart. Conventional chemotherapy has a very low effectiveness; despite recent efforts, there is currently no better or more effective treatment available. DNA vaccines provide a new alternative for both prevention and treatment of a variety of infectious disorders, including Chagas disease. Recombinant DNA technology has allowed some vaccines to be developed using recombinant proteins or virus-like particles capable of inducing both a humoral and cellular specific immune response. This type of immunization has been successfully used in preclinical studies and there are diverse models for viral, bacterial and/or parasitic diseases, allergies, tumors and other diseases. Therefore, several research groups have been given the task of designing a DNA vaccine against experimental infection with T. cruzi. In this review we explain what DNA vaccines are and the most recent studies that have been done to develop them with prophylactic or therapeutic purposes against Chagas disease.

  8. Scrutinizing the Biomarkers for the Neglected Chagas Disease: How Remarkable!

    PubMed Central

    Pinho, Rosa T.; Waghabi, Mariana C.; Cardillo, Fabíola; Mengel, José; Antas, Paulo R. Z.

    2016-01-01

    Biomarkers or biosignature profiles have become accessible over time in population-based studies for Chagas disease. Thus, the identification of consistent and reliable indicators of the diagnosis and prognosis of patients with heart failure might facilitate the prioritization of therapeutic management to those with the highest chance of contracting this disease. The purpose of this paper is to review the recent state and the upcoming trends in biomarkers for human Chagas disease. As an emerging concept, we propose a classification of biomarkers based on plasmatic-, phenotype-, antigenic-, genetic-, and management-related candidates. The available data revisited here reveal the lessons learned thus far and the existing challenges that still lie ahead to enable biomarkers to be employed consistently in risk evaluation for this disease. There is a strong need for biomarker validation, particularly for biomarkers that are specific to the clinical forms of Chagas disease. The current failure to achieve the eradication of the transmission of this disease has produced determination to solve this validation issue. Finally, it would be strategic to develop a wide variety of biomarkers and to test them in both preclinical and clinical trials. PMID:27563302

  9. Trypanosoma cruzi and Chagas' Disease in the United States

    PubMed Central

    Bern, Caryn; Kjos, Sonia; Yabsley, Michael J.; Montgomery, Susan P.

    2011-01-01

    Summary: Chagas' disease is caused by the protozoan parasite Trypanosoma cruzi and causes potentially life-threatening disease of the heart and gastrointestinal tract. The southern half of the United States contains enzootic cycles of T. cruzi, involving 11 recognized triatomine vector species. The greatest vector diversity and density occur in the western United States, where woodrats are the most common reservoir; other rodents, raccoons, skunks, and coyotes are also infected with T. cruzi. In the eastern United States, the prevalence of T. cruzi is highest in raccoons, opossums, armadillos, and skunks. A total of 7 autochthonous vector-borne human infections have been reported in Texas, California, Tennessee, and Louisiana; many others are thought to go unrecognized. Nevertheless, most T. cruzi-infected individuals in the United States are immigrants from areas of endemicity in Latin America. Seven transfusion-associated and 6 organ donor-derived T. cruzi infections have been documented in the United States and Canada. As improved control of vector- and blood-borne T. cruzi transmission decreases the burden in countries where the disease is historically endemic and imported Chagas' disease is increasingly recognized outside Latin America, the United States can play an important role in addressing the altered epidemiology of Chagas' disease in the 21st century. PMID:21976603

  10. Ecologic Niche Modeling and Potential Reservoirs for Chagas Disease, Mexico.

    PubMed Central

    Sánchez-Cordero, Victor; Ben Beard, C.; Ramsey, Janine M.

    2002-01-01

    Ecologic niche modeling may improve our understanding of epidemiologically relevant vector and parasite-reservoir distributions. We used this tool to identify host relationships of Triatoma species implicated in transmission of Chagas disease. Associations have been documented between the protracta complex (Triatoma: Triatominae: Reduviidae) with packrat species (Neotoma spp.), providing an excellent case study for the broader challenge of developing hypotheses of association. Species pairs that were identified coincided exactly with those in previous studies, suggesting that local interactions between Triatoma and Neotoma species and subspecies have implications at a geographic level. Nothing is known about sylvatic associates of T. barberi, which are considered the primary Chagas vector in Mexico; its geographic distribution coincided closely with that of N. mexicana, suggesting interaction. The presence of the species was confirmed in two regions where it had been predicted but not previously collected. This approach may help in identifying Chagas disease risk areas, planning vector-control strategies, and exploring parasite-reservoir associations for other emerging diseases. PMID:12095431

  11. The Role of Haptoglobin Genotypes in Chagas Disease

    PubMed Central

    Mundaray Fernández, Ninomar; Fernández-Mestre, Mercedes

    2014-01-01

    Although the number of people infected with T. cruzi is on the rise, host genetic and immune components that are crucial in the development of the Chagas disease have been discovered. We investigated the frequency of polymorphisms in the gene encoding haptoglobin of patients with chronic Chagas disease. The results suggest that while the HP1-1 genotype may confer protection against infection and the development of chronic Chagas disease due to the rapid metabolism of the Hp1-1-Hb complex and its anti-inflammatory activity, the presence of HP2-2 genotype may increase susceptibility towards a chronic condition of the disease due to a slow metabolism of the Hp2-2-Hb complex, lower antioxidant activity, and increased inflammatory reactivity, which lead to cell damage and a deterioration of the cardiac function. Finally, correlations between HP genotypes in different age groups and cardiac manifestations suggest that HP polymorphism could influence the prognosis of this infectious disease. This study shows some of the relevant aspects of the haptoglobin gene polymorphism and its implications in the T. cruzi infection. PMID:25147423

  12. Opportunity Cost for Early Treatment of Chagas Disease in Mexico

    PubMed Central

    Ramsey, Janine M.; Elizondo-Cano, Miguel; Sanchez-González, Gilberto; Peña-Nieves, Adriana; Figueroa-Lara, Alejandro

    2014-01-01

    Background Given current neglect for Chagas disease in public health programs in Mexico, future healthcare and economic development policies will need a more robust model to analyze costs and impacts of timely clinical attention of infected populations. Methodology/Principal Findings A Markov decision model was constructed to simulate the natural history of a Chagas disease cohort in Mexico and to project the associated short and long-term clinical outcomes and corresponding costs. The lifetime cost for a timely diagnosed and treated Chagas disease patient is US$ 10,160, while the cost for an undiagnosed individual is US$ 11,877. The cost of a diagnosed and treated case increases 24-fold from early acute to indeterminate stage. The major cost component for lifetime cost was working days lost, between 44% and 75%, depending on the program scenario for timely diagnosis and treatment. Conclusions/Significance In the long term, it is cheaper to diagnose and treat chagasic patients early, instead of doing nothing. This finding by itself argues for the need to shift current policy, in order to prioritize and attend this neglected disease for the benefit of social and economic development, which implies including treatment drugs in the national formularies. Present results are even more relevant, if one considers that timely diagnosis and treatment can arrest clinical progression and enhance a chronic patient's quality of life. PMID:24743112

  13. On the scaling relationship between enamel prism length and enamel thickness in primate molars: a comment.

    PubMed

    Macho, Gabriele A

    2004-12-01

    As part of a larger study we developed a computer programme which allows the recreation of the complex 3-dimensional arrangement of prisms. Data presented in these earlier publications are re-analyzed to assess the relationship between projected prism length (i. e., enamel thickness) and the true prism length. Across primates, proportional prism deviation increases as the enamel becomes thicker. This supports suggestions that prism decussation may be particularly marked in large-bodied and thick-enameled species. There are differences, however, in scaling relationships between species, which correspond to the species' dietary adaptations. Finally, the findings highlight the importance of employing species-specific correction factors for the calculation of prism length (i.e., life-span of the ameloblast) for life history enquiry.

  14. Effectiveness of prisms in the management of diplopia in patients due to diverse etiologies.

    PubMed

    Tamhankar, Madhura A; Ying, Gui-shuang; Volpe, Nicholas J

    2012-01-01

    To study the effectiveness of prisms in the management of diplopia from different etiologies and over a broad range of ocular misalignment. In this retrospective cohort study, resolution of diplopia in 94 patients who were prescribed prisms was studied. Among 94 patients, 88% reported complete or partial resolution of double vision (95% confidence interval: 84.1% to 95.6%) with highest improvement noted in the divergence insufficiency and skew deviation group (100%) compared to 64% improvement noted in patients with convergence insufficiency. More than 85% of patients who were prescribed greater than 10 diopters of prism and those with oblique prism prescriptions also reported resolution of diplopia. Eighty-nine percent of the cohort continued with prism use and 11% opted for strabismus surgery. In this study, prisms were effective in alleviation of diplopia over a broad range and for different etiologies of double vision. Copyright 2012, SLACK Incorporated.

  15. Generalization of the first-order formula for analysis of scan patterns of Risley prisms

    NASA Astrophysics Data System (ADS)

    Jeon, Yong-Geun

    2011-11-01

    A first-order formula for calculations of the direction cosines of the rays refracted by Risley prisms was derived. The formula was obtained by representing the deviation of the ray passing through a prism by the product of rotation matrices, and using the series expansion of the product. It can be applied to the system of an arbitrary number of prisms or a combination of Risley prisms. Related errors were discussed and some numerical calculations were made and compared with the exact solutions using the refraction equation. The scan patterns of a single Risley prism or a combination of two Risley prisms calculated using the generalized first-order formula are in good agreement with the exact solutions.

  16. Prism-coupled compound parabola: a new ideal and optimal solar concentrator.

    PubMed

    Edmonds, I R

    1986-08-01

    A concentrator consisting of a compound parabola with foci at the apex of a prism is described. Design equations for the concentrator are derived, and it is shown that the concentrator is ideal and achieves the maximum theoretical concentration n/sin theta for specific values of prism apex angle and refractive index n of prism material. Truncation equations are given, and advantages of this concentrator relative to the compound parabolic concentrator are briefly discussed.

  17. Asymmetric transmission in prisms using structures and materials with isotropic-type dispersion.

    PubMed

    Gundogdu, Funda Tamara; Serebryannikov, Andriy E; Cakmak, A Ozgur; Ozbay, Ekmel

    2015-09-21

    It is demonstrated that strong asymmetry in transmission can be obtained at the Gaussian beam illumination for a single prism based on a photonic crystal (PhC) with isotropic-type dispersion, as well as for its analog made of a homogeneous material. Asymmetric transmission can be realized with the aid of refraction at a proper orientation of the interfaces and wedges of the prism, whereas neither contribution of higher diffraction orders nor anisotropic-type dispersion is required. Furthermore, incidence toward a prism wedge can be used for one of two opposite directions in order to obtain asymmetry. Thus, asymmetric transmission is a general property of the prism configurations, which can be obtained by using simple geometries and quite conventional materials. The obtained results show that strong asymmetry can be achieved in PhC prisms with (nearly) circular shape of equifrequency dispersion contours, in both cases associated with the index of refraction 01. For the comparison purposes, results are also presented for solid uniform non-magnetic prisms made of a material with the same value of n. It is shown in zero-loss approximation that the PhC prism and the ultralow-index material prism (0prism and the solid dielectric prism can show the same scenario at n>1. Possible contributions of scattering on the individual rods and diffraction on the wedge to the resulting mechanism are discussed. Analogs of unidirectional splitting and unidirectional deflection regimes, which are known from the studies of PhC gratings, are obtained in PhC prisms and solid uniform prisms, i.e. without higher diffraction orders.

  18. Prism adaptation magnitude has differential influences on perceptual versus manual responses.

    PubMed

    Striemer, Christopher L; Russell, Karyn; Nath, Priya

    2016-10-01

    Previous research has indicated that rightward prism adaptation can reduce symptoms of spatial neglect following right brain damage. In addition, leftward prism adaptation can create "neglect-like" patterns of performance in healthy adults on tasks that measure attention and spatial biases. Although a great deal of research has focused on which behaviors are influenced by prism adaptation, very few studies have focused directly on how the magnitude of visual shift induced by prisms might be related to the observed aftereffects, or the effects of prisms on measures of attentional and spatial biases. In the current study, we examined these questions by having groups of healthy adult participants complete manual line bisection and landmark tasks prior to and following adaptation to either 8.5° (15 diopter; n = 22) or 17° (30 diopter; n = 25) leftward shifting prisms. Our results demonstrated a significantly larger rightward shift in straight-ahead pointing (a measure of prism aftereffect) following adaptation to 17°, compared to 8.5° leftward shifting prisms. In addition, only 17° leftward shifting prisms resulted in a significant rightward shift in line bisection following adaptation. However, there was a significant change in performance on the landmark task pre- versus post-adaptation in both the 8.5° and 17° leftward shifting prism groups. Interestingly, correlation analyses indicated that changes in straight-ahead pointing pre- versus post-adaptation were positively correlated with changes in performance on the manual line bisection task, but not the landmark task. These data suggest that larger magnitudes of prism adaptation seem to have a greater influence on tasks that require a response with the adapted hand (i.e., line bisection), compared to tasks that only require a perceptual judgment (i.e., the landmark task). In addition, these data provide further evidence that the effects of prisms on manual and perceptual responses are not related to one

  19. Chagas Disease Screening in Maternal Donors of Publicly Banked Umbilical Cord Blood, United States

    PubMed Central

    Gilner, Jennifer B.; Hernandez, Jose; Kurtzberg, Joanne; Heine, R. Phillips

    2016-01-01

    To assess patterns of Chagas disease, we reviewed results of screening umbilical cord blood from a US public cord blood bank during 2007–2014. Nineteen maternal donors tested positive for Trypanosoma cruzi parasites (0.04%). Because perinatal transmission of Chagas disease is associated with substantial illness, targeted prenatal programs should screen for this disease. PMID:27433974

  20. Prevention of congenital Chagas disease by Benznidazole treatment in reproductive-age women. An observational study.

    PubMed

    Álvarez, María G; Vigliano, Carlos; Lococo, Bruno; Bertocchi, Graciela; Viotti, Rodolfo

    2017-10-01

    Since the decline in new cases of infection by insect/vector, congenital Chagas disease has become more relevant in the transmission of Chagas disease. Treatment with benznidazole significantly reduces the parasitemia, which constitutes an important factor linked to vertical transmission. The objective of this study was to evaluate whether treatment with benznidazole previously administered to women of childbearing age can prevent or reduce the incidence of new cases of congenital Chagas disease. An historical cohort study that included all women in reproductive age (15-45 years) assisted in our center was designed. We included 67 mothers with chronic Chagas disease; 35 women had not been treated prior to pregnancy, 15 had been treated prior to pregnancy and 17 gave birth prior and after treatment with benznidazole. Eight mothers gave birth to 16 children with congenital Chagas disease (8/67, 12%). The prevalence of congenital Chagas was 16/114 (14%) children born to untreated mothers and 0/42 (0%) children born to benznidazole- treated mothers, p=0.01. No significant differences were observed in clinical, serologic, epidemiological or socioeconomic baseline variables between mothers with and without children born with congenital Chagas. A 32% conversion rate to negative serology was observed in benznidazole-treated women after long-term follow up. Antiparasitic treatment administered to women in reproductive age can prevent the occurrence of congenital Chagas disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Evaluation of Right Ventricular Systolic Function in Chagas Disease Using Cardiac Magnetic Resonance Imaging.

    PubMed

    Moreira, Henrique T; Volpe, Gustavo J; Marin-Neto, José A; Ambale-Venkatesh, Bharath; Nwabuo, Chike C; Trad, Henrique S; Romano, Minna M D; Pazin-Filho, Antonio; Maciel, Benedito C; Lima, João A C; Schmidt, André

    2017-03-01

    Right ventricular (RV) impairment is postulated to be responsible for prominent systemic congestion in Chagas disease. However, occurrence of primary RV dysfunction in Chagas disease remains controversial. We aimed to study RV systolic function in patients with Chagas disease using cardiac magnetic resonance. This cross-sectional study included 158 individuals with chronic Chagas disease who underwent cardiac magnetic resonance. RV systolic dysfunction was defined as reduced RV ejection fraction based on predefined cutoffs accounting for age and sex. Multivariable logistic regression was used to verify the relationship of RV systolic dysfunction with age, sex, functional class, use of medications for heart failure, atrial fibrillation, and left ventricular systolic dysfunction. Mean age was 54±13 years, 51.2% men. RV systolic dysfunction was identified in 58 (37%) individuals. Although usually associated with reduced left ventricular ejection fraction, isolated RV systolic dysfunction was found in 7 (4.4%) patients, 2 of them in early stages of Chagas disease. Presence of RV dysfunction was not significantly different in patients with indeterminate/digestive form of Chagas disease (35.7%) compared with those with Chagas cardiomyopathy (36.8%) (P=1.000). In chronic Chagas disease, RV systolic dysfunction is more commonly associated with left ventricular systolic dysfunction, although isolated and early RV dysfunction can also be identified. © 2017 American Heart Association, Inc.

  2. Fatal congenital Chagas' disease in a non-endemic area: a case report

    PubMed Central

    Flores-Chávez, María; Faez, Yamile; Olalla, José M; Cruz, Israel; Gárate, Teresa; Rodríguez, Mercedes; Blanc, Pilar; Cañavate, Carmen

    2008-01-01

    The early diagnosis of congenital Chagas' disease is very important if infected newborns, whether symptomatic or not, are to receive adequate treatment. This paper describes the complications arising in the diagnosis of a newborn with fatal congenital Chagas' disease in Spain, a non-endemic area where visceral leishmaniasis is present. PMID:18992159

  3. Community-based trial of a peripheral prism visual field expansion device for hemianopia.

    PubMed

    Bowers, Alex R; Keeney, Karen; Peli, Eli

    2008-05-01

    To determine the functional utility for general mobility of peripheral prism glasses, a novel visual field expansion device for hemianopia, in a large-scale, community-based, multicenter study with long-term follow-up. Forty-three participants with homonymous hemianopia were fitted with temporary press-on Fresnel peripheral prism segments of 40 prism diopters. Follow-up questionnaires evaluating functional benefits for mobility were administered in the office at week 6. Participants who continued wearing the prisms were interviewed again by telephone after a median of 12 months. Primary outcome measures included clinical success (a clinical decision to continue wear) and 5-point ratings of prism helpfulness for obstacle avoidance when walking. Thirty-two participants (74%) continued prism wear at week 6, and 20 (47%) were still wearing the prisms after 12 months (median time, 8 hours per day). These participants rated the prism glasses as very helpful for obstacle avoidance and reported significant benefits for obstacle avoidance in a variety of mobility situations. Success rates varied among clinic groups (27%-81%), with higher rates at the clinics that fitted more patients. Our results demonstrate the functional utility of peripheral prism glasses as a general mobility aid for patients with hemianopia.

  4. Randomized crossover clinical trial of real and sham peripheral prism glasses for hemianopia

    PubMed Central

    Bowers, Alex R.; Keeney, Karen; Peli, Eli

    2013-01-01

    Objective To evaluate the efficacy of real relative to sham peripheral prism glasses for patients with complete homonymous hemianopia and without visual neglect. Methods Patients recruited at 13 clinics were allocated by minimization into a double-masked, crossover trial with two groups. One group received real (57Δ) oblique and sham (≤ 5Δ) horizontal prisms; the other received real horizontal and sham oblique, in counterbalanced order. A masked data collector at each clinic administered questionnaires after each 4-week crossover period. Main outcome measure The primary outcome was the overall difference, across the two periods of the crossover, between the proportion of participants who wanted to continue with (said “yes” to) real prisms and the proportion who said yes to sham prisms. The secondary outcome was the difference in perceived mobility improvement between real and sham prisms. Results Of 73 patients randomized, 61 completed the crossover. A significantly higher proportion said yes to real than sham prisms (64% vs. 36%; odds ratio 5.3, 95% CI 1.8 to 21.0). Participants who continued wear after 6 months reported greater improvement in mobility with real than sham prisms at crossover end (p=0.002); participants who discontinued wear reported no difference. Conclusion Real peripheral prism glasses were more helpful for obstacle avoidance when walking than sham glasses, with no differences between the horizontal and oblique designs. Applications to clinical practice Peripheral prism glasses provide a simple and inexpensive mobility rehabilitation intervention for hemianopia. PMID:24201760

  5. Community-Based Trial of Peripheral Prism Visual Field Expansion Device for Hemianopia

    PubMed Central

    Bowers, Alex R.; Keeney, Karen; Peli, Eli

    2007-01-01

    Background Peripheral prism glasses, a novel visual field expansion device for hemianopia, showed promise in early, small-sample evaluations. Objective To determine functionality of the glasses for general mobility in a larger-scale, community-based, multi-center study with longer-term follow up. Methods Forty-three participants with homonymous hemianopia were fitted with temporary press-on™ Fresnel (40 prism diopter) peripheral prism segments. Follow up questionnaires, evaluating functional benefits for mobility, were administered in-office at week 6. Participants who continued wearing the prisms were interviewed again by telephone after 12 months (median). Primary outcome measures included: clinical success (a clinical decision to continue wear) and 5-point ratings of prism-helpfulness for obstacle avoidance when walking. Results Thirty-two participants (74%) continued prism-wear at week 6, and 20 (47%) were still wearing prisms after 12 months (8 hours per day ) rating the prism glasses as “very helpful” for obstacle avoidance and reporting significant benefits for obstacle avoidance in a variety of mobility situations. Success rates varied among clinic groups (27% to 81%), with higher rates at the clinics that fitted more patients. Conclusions Our results demonstrate the functional utility of peripheral prism glasses as a general mobility aid for hemianopic patients. PMID:18474776

  6. Regularly configured structures with polygonal prisms for three-dimensional auxetic behaviour.

    PubMed

    Kim, Junhyun; Shin, Dongheok; Yoo, Do-Sik; Kim, Kyoungsik

    2017-06-01

    We report here structures, constructed with regular polygonal prisms, that exhibit negative Poisson's ratios. In particular, we show how we can construct such a structure with regular n-gonal prism-shaped unit cells that are again built with regular n-gonal component prisms. First, we show that the only three possible values for n are 3, 4 and 6 and then discuss how we construct the unit cell again with regular n-gonal component prisms. Then, we derive Poisson's ratio formula for each of the three structures and show, by analysis and numerical verification, that the structures possess negative Poisson's ratio under certain geometric conditions.

  7. Prisms are effective in resolving diplopia from incomitant, large, and combined strabismus.

    PubMed

    Tamhankar, Madhura A; Ying, Gui-Shuang; Volpe, Nicholas J

    2012-01-01

    To assess the effectiveness of prisms in the management of diplopia in patients with incomitant, large, and combined strabismus. Data were collected retrospectively from the medical records of 64 patients who were prescribed prisms for symptomatic diplopia due to restrictive strabismus. The main outcome measure was resolution of diplopia (diplopia score 1 or 2). Data on the number of patients who continued wearing prisms versus those who opted for surgery were derived based on follow-up records. Among 64 patients, 72% of patients reported complete or partial resolution of diplopia after prism use. In patients who were prescribed =10 PD (n=18) and those with oblique prisms (n=18), 67% and 50%, respectively, reported resolution of diplopia. More patients with vertical prism reported improvement in double vision symptoms (83%) than those who were prescribed horizontal prism (70%, p=0.04). During follow-up, 73% of the cohort continued using prisms while 23% of patients opted for strabismus surgery. Prisms are an effective modality and should be considered in the initial or interim management of patients with diplopia from complex ocular misalignments.

  8. Studying the neural bases of prism adaptation using fMRI: A technical and design challenge.

    PubMed

    Bultitude, Janet H; Farnè, Alessandro; Salemme, Romeo; Ibarrola, Danielle; Urquizar, Christian; O'Shea, Jacinta; Luauté, Jacques

    2016-12-30

    Prism adaptation induces rapid recalibration of visuomotor coordination. The neural mechanisms of prism adaptation have come under scrutiny since the observations that the technique can alleviate hemispatial neglect following stroke, and can alter spatial cognition in healthy controls. Relative to non-imaging behavioral studies, fMRI investigations of prism adaptation face several challenges arising from the confined physical environment of the scanner and the supine position of the participants. Any researcher who wishes to administer prism adaptation in an fMRI environment must adjust their procedures enough to enable the experiment to be performed, but not so much that the behavioral task departs too much from true prism adaptation. Furthermore, the specific temporal dynamics of behavioral components of prism adaptation present additional challenges for measuring their neural correlates. We developed a system for measuring the key features of prism adaptation behavior within an fMRI environment. To validate our configuration, we present behavioral (pointing) and head movement data from 11 right-hemisphere lesioned patients and 17 older controls who underwent sham and real prism adaptation in an MRI scanner. Most participants could adapt to prismatic displacement with minimal head movements, and the procedure was well tolerated. We propose recommendations for fMRI studies of prism adaptation based on the design-specific constraints and our results.

  9. Terahertz time domain attenuated total reflection spectroscopy with an integrated prism system.

    PubMed

    Nakanishi, Atsushi; Kawada, Yoichi; Yasuda, Takashi; Akiyama, Koichiro; Takahashi, Hironori

    2012-03-01

    We demonstrated attenuated total reflection (ATR) spectroscopy with an integrated prism system that included a terahertz emitter, a terahertz receiver, and an ATR prism. The ATR prism had two internal off-axis parabolic mirrors for, respectively, collimating and focusing the terahertz waves. The Fresnel loss at each interface was reduced, and the total propagation efficiency was 3.36 times larger than when using a non-integrated prism system. The refractive index of water samples calculated from the experimental data showed good agreement with values reported in the literature.

  10. Outcome of intensive care unit patients using Pediatric Risk of Mortality (PRISM) score.

    PubMed

    Bellad, Roopa; Rao, Surendra; Patil, V D; Mahantshetti, N S

    2009-12-01

    We conducted this study to evaluate the outcome of 203 patients admitted to PICU, using PRISM score. Overall mortality was 16.7%. The mean PRISM score was 6.5+/-3.6 and 15.5+/-7 for survivors and non survivors, respectively (OR: 1.36; 95% CI=1.24 -1.5; P<0.001). PRISM score also correlated well with length of hospital stay and the number of organ failures (P<0.001). A cut off score of 15 was associated with 89.2% accuracy. PRISM score is highly sensitive in predicting the outcome of pediatric patients in an ICU setting.

  11. Separation of multiple images via directional guidance using structured prism and pyramid arrays.

    PubMed

    Lee, Hyemin; Seo, Hyein; Kang, Sunghwan; Yoon, Hyunsik

    2016-09-05

    We propose a new concept of separating images through a directional guide of multi-visuals by using structured prism or pyramid arrays. By placing prism arrays onto two different image arrays, the two collective images below the facets are guided to different directions. Using optical calculations, we identify a condition for successful image separation. Transparent pyramid arrays are used to separate four images into four directions. The direction of refracted rays can be controlled by the refractive index of prisms and liquid filled into the voids. In addition, the images can be switched by stretching and releasing an elastomeric prism array.

  12. Acute Chagas Disease: New Global Challenges for an Old Neglected Disease

    PubMed Central

    Andrade, Daniela V.; Gollob, Kenneth J.; Dutra, Walderez O.

    2014-01-01

    Chagas disease is caused by infection with the protozoan Trypanosoma cruzi, and although over 100 years have passed since the discovery of Chagas disease, it still presents an increasing problem for global public health. A plethora of information concerning the chronic phase of human Chagas disease, particularly the severe cardiac form, is available in the literature. However, information concerning events during the acute phase of the disease is scarce. In this review, we will discuss (1) the current status of acute Chagas disease cases globally, (2) the immunological findings related to the acute phase and their possible influence in disease outcome, and (3) reactivation of Chagas disease in immunocompromised individuals, a key point for transplantation and HIV infection management. PMID:25077613

  13. From Lemongrass to Ivermectin: Ethnomedical Management of Chagas Disease in Tropical Bolivia.

    PubMed

    Forsyth, Colin

    2017-07-31

    Chagas disease is a neglected tropical disease; the only viable drugs are outdated and produce frequent side effects, and the overwhelming majority of cases are undiagnosed and untreated. Globally, people encounter numerous impediments to accessing biomedical treatment for Chagas disease. However, little is known about how people with Chagas disease manage their health outside the biomedical system. In this article, I discuss knowledge of ethnomedical treatments among marginalized patients in an endemic area of Bolivia. I interviewed 68 patients, 63 (93 percent) of whom had positive diagnoses for Chagas disease. Participants free listed 66 ethnomedical remedies either for Chagas disease (n = 39) or its cardiac symptoms. Participants stressed the accessibility of ethnomedical remedies in contrast to the multiple barriers to accessing biomedical treatment. Far from eroding in the face of globalization and sociopolitical marginalization, ethnomedical knowledge in the study area is dynamic and flexible, communicated through various channels.

  14. EUCLID: design of the prism DMD NIR spectrograph

    NASA Astrophysics Data System (ADS)

    Content, Robert; Sharples, Ray M.; Blake, Simon; Talbot, R. Gordon

    2010-07-01

    EUCLID, the ESA Dark Energy Mission, contains a NIR and a visible imagers (NIP & VIS), and an NIR spectrograph (NIS). Different designs of the NIS have been studied especially a slitless design, a Digital Micromirror Device (DMD) design using grisms and another using prisms, and more recently a combination of the NIP and NIS into one instrument. We present the design of the prism DMD NIS. This design has the advantage over the slitless design of having a DMD mask which reduces the background by a factor of more than 100 and all the advantages over the grism DMD NIS that a prism gives over a grism as a higher and more uniform transmission, the absence of parasite orders, and a choice of the slope of the spectral resolution with wavelength. The field per spectrograph was made sufficiently large to reduce the number of spectrographs to two. The design was made so that the mapping of the sky of the NIS is easily compatible with the mapping strategy of the NIP and VIS. Two designs were made. In one, the field is larger but the surface shapes of the optics are complex which makes manufacturing more challenging. In the other, the design was made to be fully compatible with the manufacturing criteria of SESO after extensive discussions to carefully understand the manufacturing limitations especially the formula for highly aspheric surface shapes as biconics. This was done by directly integrating the criteria into the optimization process of ZEMAX. A calibration system that uses the DMD with the micromirrors in their OFF positions was also developed.

  15. Overland Tidal Power Generation Using Modular Tidal Prism

    SciTech Connect

    Khangaonkar, Tarang; Yang, Zhaoqing; Geerlofs, Simon H.; Copping, Andrea

    2010-03-01

    Naturally occurring sites with sufficient kinetic energy suitable for tidal power generation with sustained currents > 1 to 2 m/s are relatively rare. Yet sites with greater than 3 to 4 m of tidal range are relatively common around the U.S. coastline. Tidal potential does exist along the shoreline but is mostly distributed, and requires an approach which allows trapping and collection to also be conducted in a distributed manner. In this paper we examine the feasibility of generating sustainable tidal power using multiple nearshore tidal energy collection units and present the Modular Tidal Prism (MTP) basin concept. The proposed approach utilizes available tidal potential by conversion into tidal kinetic energy through cyclic expansion and drainage from shallow modular manufactured overland tidal prisms. A preliminary design and configuration of the modular tidal prism basin including inlet channel configuration and basin dimensions was developed. The unique design was shown to sustain momentum in the penstocks during flooding as well as ebbing tidal cycles. The unstructured-grid finite volume coastal ocean model (FVCOM) was used to subject the proposed design to a number of sensitivity tests and to optimize the size, shape and configuration of MTP basin for peak power generation capacity. The results show that an artificial modular basin with a reasonable footprint (≈ 300 acres) has the potential to generate 10 to 20 kw average energy through the operation of a small turbine located near the basin outlet. The potential of generating a total of 500 kw to 1 MW of power through a 20 to 40 MTP basin tidal power farms distributed along the coastline of Puget Sound, Washington, is explored.

  16. Analytic PRISM theory of structurally asymmetric polymer blends and copolymers

    SciTech Connect

    Schweizer, K.S. )

    1993-10-25

    Analytic PRISM theory with the new molecular closures is applied to determine the effective chi-parameters and spinodal instability curves for structurally asymmetric polymer alloys. Compressibility effects are found to be very important, and the use of a literal incompressible RPA-like approximation is shown to incur qualitative errors in most cases. A rich and nonadditive dependence of phase transition temperatures and apparent SANS chi-parameters on backbone stiffness asymmetry, attractive interaction potential asymmetry, and thermodynamic variables is found for binary homopolymer blends. A novel strategy for designing miscible mixtures based on a cancellation, or compensation, of the relevant asymmetries is identified. The influence of chain stiffness asymmetry in blends characterized by specific interactions is also studied. Generalization of the analytic PRISM theory to mixtures of random copolymers and periodic block copolymer melts is presented. All the rich behavior predicted for phase-separating homopolymer mixtures is again found for these systems, plus additional non mean field effects associated with random copolymer composition and block architecture. The theory is applied semiquantitatively to interpret recent experiments on polyolefin blends, diblock copolymers, and random copolymer alloys. Theoretical predictions are made which qualitatively account for recent experimental observations of a strong influence of stiffness asymmetry on phase separation temperatures, and the breakdown of the mean field random copolymer approach. Anomalous behavior is also predicted for deuterated mixtures due to an interference between the consequences of stiffness asymmetry and enthalipic interactions. The physical mechanism for the many non-Flory-Huggins effects predicted by the compressible PRISM theory is local, scalar density correlations, which appears to be different than the nematic fluctuation mechanism suggested by recent field theoretic work.

  17. The PRISM palaeoclimate reconstruction and Pliocene sea-surface temperature

    USGS Publications Warehouse

    Dowsett, H.J.; ,

    2007-01-01

    In this paper, I present a summary of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) palaeoenvironmental reconstruction, with emphasis on its historical development and range of boundary condition datasets. Sea-surface temperature (SST), sea level, sea ice, land cover (vegetation and ice) and topography are discussed as well as many of the assumptions required to create an integrated global-scale reconstruction. New multiproxy research shows good general agreement on the magnitude of mid-Pliocene SST warming. Future directions, including maximum and minimum SST analyses and deep ocean temperature estimates aimed at a full three-dimensional reconstruction, are presented. ?? The Micropalaeontological Society 2007.

  18. Description of the PRISM system architecture and user interface

    NASA Astrophysics Data System (ADS)

    Constanza, P.; Larsson, C.; Thiemann, H.; Wedi, N.

    2003-04-01

    The PRISM system architecture enables the user to perform numerical experiments, allowing to couple interchangeable model components, e.g. atmosphere, ocean, biosphere, chemistry, via standardised interfaces. The coupler is based on standard interfaces implemented in the different model components. The exchange of data between the components will occur either in a direct way between components or through the coupler. The general architecture provides the infrastructure to configure, submit, monitor and subsequently post process, archive and diagnose the results of these coupled model experiments. There is an emphasis on choosing an architectural design that allows these activities to be done remotely, e.g. without the user physically being in the same place where the numerical computations take place. The PRISM general architecture gives the choice to the user either to work locally or to work through a central PRISM site where the user will be registered. Locally or via the Internet, the user will be able to use the same graphical user interface. The choice will depend of the local availability of the required resources. In addition a supervisor monitor program (SMS) gives full control over model simulations during run-time. The technology that realises the proposed architecture is known as "Web services". This includes the use of web servers, application servers, resource directories, discovery mechanisms and messages services. Currently there is no client software that can be used with browsers that does not build on Java technology. Java supports all the mechanisms needed for implementing web services using available standards. From a system maintenance point of view using one technology, Java, is the preferred way as this simplifies the task of adhering to multiple standards. The issue of standardisation of interfaces is important for complex and configurable systems such as PRISM. For example the extensible Markup Language (XML) allows for standardisation of

  19. Polarization manipulation in single refractive prism based holography lithography

    NASA Astrophysics Data System (ADS)

    Xiong, Wenjie; Xu, Yi; Xiao, Yujian; Lv, Xiaoxu; Wu, Lijun

    2015-01-01

    We propose theoretically and demonstrate experimentally a simple but effective strategy for polarization manipulation in single refractive prism based holographic lithography. By tuning the polarization of a single laser beam, we can obtain the pill shape interference pattern with a high-contrast where a complex optical setup and multiple polarizers are needed in the conventional holography lithography. Fabrication of pill shape two-dimensional polymer photonic crystals using one beam and one shoot holography lithography is shown as an example to support our theoretical results. This integrated polarization manipulation technique can release the crucial stability restrictions imposed on the multiple beams holography lithography.

  20. Sealed One Piece Battery Having A Prism Shape Container

    DOEpatents

    Verhoog, Roelof; Barbotin, Jean-Loup

    2000-03-28

    A sealed one-piece battery having a prism-shaped container including: a tank consisting of a single plastic material, a member fixed and sealed to the tank and to partitions on the side of the tank opposite the transverse wall to seal the tank, two flanges fixed and sealed to longitudinal walls defining flow compartments for a heat-conducting fluid, and two tubes on the transverse wall of the tank forming an inlet and an outlet for fluid common to the compartments.

  1. Fano resonances in prism-coupled multimode square micropillar resonators

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Tong; Zhou, Linjie; Poon, Andrew W.

    2005-06-01

    We report Fano resonances in a multimode square glass micropillar resonator; the resonances were obtained by using angle-resolved prism coupling. Our experiments reveal characteristically asymmetric line shapes of high-Q resonances and of detuned low-Q resonances in multimode reflection spectra. The asymmetric resonance line shapes evolve for an approximately pi phase within a 0.5° range of reflection angles. We model our observed asymmetric multimode resonances by the far-field interference between a light wave that is evanescently coupled with a high-Q mode orbit and a coherent light wave that is refractively coupled with a detuned low-Q mode orbit.

  2. Challenges in the management of Chagas disease in Latin-American migrants in Europe.

    PubMed

    Monge-Maillo, B; López-Vélez, R

    2017-05-01

    Chagas disease is endemic in Latin America. Due to migration the infection has crossed borders and it is estimated that 68,000-120,000 people with Chagas disease are currently living in Europe and 30% of them may develop visceral involvement. However, up to 90% of Chagas disease cases in Europe remain undiagnosed. The challenges which have to be overcome in Chagas disease in non-endemic countries are focused on related downing barriers to health care access, and related to screening, diagnostic tools and therapeutic management. The aim of this review is to highlight how healthcare management for Latin American migrants with Chagas disease in Europe may be improved. Medical literature was searched using PubMed. No limits were placed with respect to the language or date of publication although most of the articles selected were articles published in the last five years. Chosen search terms were "Chagas disease" AND ("migrants" OR "screening" OR "transmission" OR "treatment"; OR "knowledge" OR "non-endemic countries"); migrants AND ("Public health" OR "Health Service Accessibility" OR "Delivery of Health care"); and "Congenital Chagas disease". Healthcare management of migrant populations with Chagas disease in Europe has to be improved: -Surveillance programmes are needed to measure the burden of the disease; -screening programmes are needed; -administrative and cultural barriers in the access to health care for migrants should be reduced; -education programmes on Chagas disease should be performed -research on new diagnostic tools and therapeutic options are required. This review highlights the needs of profound changes in the health care of Latin American migrants with Chagas disease in Europe. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  3. Accuracy of a Rapid Diagnostic Test (Cypress Chagas Quick Test(®)) for the Diagnosis of Chronic Chagas Disease in a Nonendemic Area: A Retrospective Longitudinal Study.

    PubMed

    Angheben, Andrea; Staffolani, Silvia; Anselmi, Mariella; Tais, Stefano; Degani, Monica; Gobbi, Federico; Buonfrate, Dora; Gobbo, Maria; Bisoffi, Zeno

    2017-08-14

    We analyzed the accuracy of Chagas Quick Test(®), a rapid diagnostic test, for the diagnosis of chronic Chagas disease through a retrospective study on a cohort of 669 patients consecutively examined at a single reference center in Italy, during a 7-year period. We observed high concordance with serological reference standard but low accuracy for screening purposes (sensitivity/specificity: 82.8%/98.7%) at least in our nonendemic context.

  4. Randomized crossover clinical trial of real and sham peripheral prism glasses for hemianopia.

    PubMed

    Bowers, Alex R; Keeney, Karen; Peli, Eli

    2014-02-01

    There is a major lack of randomized controlled clinical trials evaluating the efficacy of prismatic treatments for hemianopia. Evidence for their effectiveness is mostly based on anecdotal case reports and open-label evaluations without a control condition. To evaluate the efficacy of real relative to sham peripheral prism glasses for patients with complete homonymous hemianopia. Double-masked, randomized crossover trial at 13 study sites, including the Peli laboratory at Schepens Eye Research Institute, 11 vision rehabilitation clinics in the United States, and 1 in the United Kingdom. Patients were 18 years or older with complete homonymous hemianopia for at least 3 months and without visual neglect or significant cognitive decline. Patients were allocated by minimization into 2 groups. One group received real (57-prism diopter) oblique and sham (<5-prism diopter) horizontal prisms; the other received real horizontal and sham oblique, in counterbalanced order. Each crossover period was 4 weeks. The primary outcome was the overall difference, across the 2 periods of the crossover, between the proportion of participants who wanted to continue with (said yes to) real prisms and the proportion who said yes to sham prisms. The secondary outcome was the difference in perceived mobility improvement between real and sham prisms. Of 73 patients randomized, 61 completed the crossover. A significantly higher proportion said yes to real than sham prisms (64% vs 36%; odds ratio, 5.3; 95% CI, 1.8-21.0). Participants who continued wear after 6 months reported greater improvement in mobility with real than sham prisms at crossover end (P = .002); participants who discontinued wear reported no difference. Real peripheral prism glasses were more helpful for obstacle avoidance when walking than sham glasses, with no differences between the horizontal and oblique designs. Peripheral prism glasses provide a simple and inexpensive mobility rehabilitation intervention for hemianopia

  5. A Pilot Study of Perceptual-Motor Training for Peripheral Prisms

    PubMed Central

    Houston, Kevin E.; Bowers, Alex R.; Fu, Xianping; Liu, Rui; Goldstein, Robert B.; Churchill, Jeff; Wiegand, Jean-Paul; Soo, Tim; Tang, Qu; Peli, Eli

    2016-01-01

    Purpose Peripheral prisms (p-prisms) shift peripheral portions of the visual field of one eye, providing visual field expansion for patients with hemianopia. However, patients rarely show adaption to the shift, incorrectly localizing objects viewed within the p-prisms. A pilot evaluation of a novel computerized perceptual-motor training program aiming to promote p-prism adaption was conducted. Methods Thirteen patients with hemianopia fitted with 57Δ oblique p-prisms completed the training protocol. They attended six 1-hour visits reaching and touching peripheral checkerboard stimuli presented over videos of driving scenes while fixating a central target. Performance was measured at each visit and after 3 months. Results There was a significant reduction in touch error (P = 0.01) for p-prism zone stimuli from pretraining median of 16.6° (IQR 12.1°–19.6°) to 2.7° ( IQR 1.0°–8.5°) at the end of training. P-prism zone reaction times did not change significantly with training (P > 0.05). P-prism zone detection improved significantly (P = 0.01) from a pretraining median 70% (IQR 50%–88%) to 95% at the end of training (IQR 73%–98%). Three months after training improvements had regressed but performance was still better than pretraining. Conclusions Improved pointing accuracy for stimuli detected in prism-expanded vision of patients with hemianopia wearing 57Δ oblique p-prisms is possible and training appears to further improve detection. Translational Relevance This is the first use of this novel software to train adaptation of visual direction in patients with hemianopia wearing peripheral prisms. PMID:26933522

  6. Kinematic markers dissociate error correction from sensorimotor realignment during prism adaptation.

    PubMed

    O'Shea, Jacinta; Gaveau, Valérie; Kandel, Matthieu; Koga, Kazuo; Susami, Kenji; Prablanc, Claude; Rossetti, Yves

    2014-03-01

    This study investigated the motor control mechanisms that enable healthy individuals to adapt their pointing movements during prism exposure to a rightward optical shift. In the prism adaptation literature, two processes are typically distinguished. Strategic motor adjustments are thought to drive the pattern of rapid endpoint error correction typically observed during the early stage of prism exposure. This is distinguished from so-called 'true sensorimotor realignment', normally measured with a different pointing task, at the end of prism exposure, which reveals a compensatory leftward 'prism after-effect'. Here, we tested whether each mode of motor compensation - strategic adjustments versus 'true sensorimotor realignment' - could be distinguished, by analyzing patterns of kinematic change during prism exposure. We hypothesized that fast feedforward versus slower feedback error corrective processes would map onto two distinct phases of the reach trajectory. Specifically, we predicted that feedforward adjustments would drive rapid compensation of the initial (acceleration) phase of the reach, resulting in the rapid reduction of endpoint errors typically observed early during prism exposure. By contrast, we expected visual-proprioceptive realignment to unfold more slowly and to reflect feedback influences during the terminal (deceleration) phase of the reach. The results confirmed these hypotheses. Rapid error reduction during the early stage of prism exposure was achieved by trial-by-trial adjustments of the motor plan, which were proportional to the endpoint error feedback from the previous trial. By contrast, compensation of the terminal reach phase unfolded slowly across the duration of prism exposure. Even after 100 trials of pointing through prisms, adaptation was incomplete, with participants continuing to exhibit a small rightward shift in both the reach endpoints and in the terminal phase of reach trajectories. Individual differences in the degree of

  7. A Pilot Study of Perceptual-Motor Training for Peripheral Prisms.

    PubMed

    Houston, Kevin E; Bowers, Alex R; Fu, Xianping; Liu, Rui; Goldstein, Robert B; Churchill, Jeff; Wiegand, Jean-Paul; Soo, Tim; Tang, Qu; Peli, Eli

    2016-02-01

    Peripheral prisms (p-prisms) shift peripheral portions of the visual field of one eye, providing visual field expansion for patients with hemianopia. However, patients rarely show adaption to the shift, incorrectly localizing objects viewed within the p-prisms. A pilot evaluation of a novel computerized perceptual-motor training program aiming to promote p-prism adaption was conducted. Thirteen patients with hemianopia fitted with 57Δ oblique p-prisms completed the training protocol. They attended six 1-hour visits reaching and touching peripheral checkerboard stimuli presented over videos of driving scenes while fixating a central target. Performance was measured at each visit and after 3 months. There was a significant reduction in touch error (P = 0.01) for p-prism zone stimuli from pretraining median of 16.6° (IQR 12.1°-19.6°) to 2.7° ( IQR 1.0°-8.5°) at the end of training. P-prism zone reaction times did not change significantly with training (P > 0.05). P-prism zone detection improved significantly (P = 0.01) from a pretraining median 70% (IQR 50%-88%) to 95% at the end of training (IQR 73%-98%). Three months after training improvements had regressed but performance was still better than pretraining. Improved pointing accuracy for stimuli detected in prism-expanded vision of patients with hemianopia wearing 57Δ oblique p-prisms is possible and training appears to further improve detection. This is the first use of this novel software to train adaptation of visual direction in patients with hemianopia wearing peripheral prisms.

  8. Deformation of the Nankai Trough inner accretionary prism: The role of inherited structures

    NASA Astrophysics Data System (ADS)

    Boston, Brian; Moore, Gregory F.; Jurado, María. José; Sone, Hiroki

    2016-02-01

    Accretionary prisms commonly grow seaward, with the strata of the inner prism consisting of older, previously accreted outer prism rocks overlain by thick fore-arc basin strata. We focus on the Nankai Trough inner accretionary prism using three-dimensional (3-D) seismic data and logging data from the Integrated Ocean Drilling Program (IODP). We update the 3-D seismic volume using well velocity data to better constrain deeper horizons. Interpretation of these horizons reveals multiple folds with axial surfaces that strike near parallel to modern outer prism thrust faults, and we interpret that these folds formed as a result of thrust faulting. Reactivation of one inner prism thrust fault continued until at least ˜0.44 Ma, after the modern fore-arc basin formed, indicating that the inner prism had continued deformation until that time. Structural restorations of these folded seismic horizons demonstrate that ˜580 m of slip occurred on this steeply dipping reactivated thrust after fore-arc basin formation. Structural interpretation and analysis of logging-while-drilling data, including borehole images, in the deep inner prism revealed intense deformation of a generally homogenous lithology characterized by bedding that dips steeply (60°-90°), intersected by faults and fractures that have a range of dips and densities. Our study of the deep Kumano Basin provides new insights into the structure of the inner prism and reveals that although the inner prism has partially preserved inherited outer prism structures, these older folds and faults are steeply rotated and cut by multiple fracture populations during subsequent deformation.

  9. The PRISM (Pliocene Palaeoclimate) reconstruction: Time for a paradigm shift

    USGS Publications Warehouse

    Dowsett, Harry J.; Robinson, Marci M.; Stoll, Danielle K.; Foley, Kevin M.; Johnson, Andrew L. A.; Williams, Mark; Riesselman, Christina

    2013-01-01

    Global palaeoclimate reconstructions have been invaluable to our understanding of the causes and effects of climate change, but single-temperature representations of the oceanic mixed layer for data–model comparisons are outdated, and the time for a paradigm shift in marine palaeoclimate reconstruction is overdue. The new paradigm in marine palaeoclimate reconstruction stems the loss of valuable climate information and instead presents a holistic and nuanced interpretation of multi-dimensional oceanographic processes and responses. A wealth of environmental information is hidden within the US Geological Survey's Pliocene Research,Interpretation and Synoptic Mapping (PRISM) marine palaeoclimate reconstruction, and we introduce here a plan to incorporate all valuable climate data into the next generation of PRISM products. Beyond the global approach and focus, we plan to incorporate regional climate dynamics with emphasis on processes, integrating multiple environmental proxies wherever available in order to better characterize the mixed layer, and developing a finer time slice within the Mid-Piacenzian Age of the Pliocene, complemented by underused proxies that offer snapshots into environmental conditions. The result will be a proxy-rich, temporally nested, process-oriented approach in a digital format - a relational database with geographic information system capabilities comprising a three-dimensional grid representing the surface layer, with a plethora of data in each cell.

  10. Composite Yb:YAG/SiC-prism thin disk laser.

    PubMed

    Newburgh, G A; Michael, A; Dubinskii, M

    2010-08-02

    We report the first demonstration of a Yb:YAG thin disk laser wherein the gain medium is intracavity face-cooled through bonding to an optical quality SiC prism. Due to the particular design of the composite bonded Yb:YAG/SiC-prism gain element, the laser beam impinges on all refractive index interfaces inside the laser cavity at Brewster's angles. The laser beam undergoes total internal reflection (TIR) at the bottom of the Yb(10%):YAG thin disk layer in a V-bounce cavity configuration. Through the use of TIR and Brewster's angles, no optical coatings, either anti-reflective (AR) or highly reflective (HR), are required inside the laser cavity. In this first demonstration, the 936.5-nm diode pumped laser performed with approximately 38% slope efficiency at 12 W of quasi-CW (Q-CW) output power at 1030 nm with a beam quality measured at M(2) = 1.5. This demonstration opens up a viable path toward novel thin disk laser designs with efficient double-sided room-temperature heatsinking via materials with the thermal conductivity of copper on both sides of the disk.

  11. Mirror symmetrical transfer of perceptual learning by prism adaptation.

    PubMed

    Tanaka, Yasuto; Miyauchi, Satoru; Misaki, Masaya; Tashiro, Takara

    2007-05-01

    Recent study of [Sugita, Y. (1996) Global plasticity in adult visual cortex following reversal of visual input. Nature, 380, 523-526.] demonstrated that prism adaptation to reversed retinal input generates the transfer of neuronal activities in monkey V1 to the opposite visual cortex. This raises the question if perceptual learning on one side of the visual field can transfer to the other side. We tested this in using the Gabor lateral masking paradigm. Before adaptation, long-range interaction was induced vertically on one side (i.e., the right) of the visual field with training (perceptual learning). Prism adaptation was achieved by wearing right-left reversing goggles. During adaptation period, perceptual learning transferred to a mirror symmetrical region across the vertical meridian. Results in the post adaptation period revealed that both learning and transfer persisted for over three months. These results provide direct evidence of transferred perceptual plasticity across the visual field, the underlying mechanism of which is supported by the mirror symmetrical connection between the right and left cortices.

  12. The PRISM (Pliocene palaeoclimate) reconstruction: time for a paradigm shift.

    PubMed

    Dowsett, Harry J; Robinson, Marci M; Stoll, Danielle K; Foley, Kevin M; Johnson, Andrew L A; Williams, Mark; Riesselman, Christina R

    2013-10-28

    Global palaeoclimate reconstructions have been invaluable to our understanding of the causes and effects of climate change, but single-temperature representations of the oceanic mixed layer for data-model comparisons are outdated, and the time for a paradigm shift in marine palaeoclimate reconstruction is overdue. The new paradigm in marine palaeoclimate reconstruction stems the loss of valuable climate information and instead presents a holistic and nuanced interpretation of multi-dimensional oceanographic processes and responses. A wealth of environmental information is hidden within the US Geological Survey's Pliocene Research, Interpretation and Synoptic Mapping (PRISM) marine palaeoclimate reconstruction, and we introduce here a plan to incorporate all valuable climate data into the next generation of PRISM products. Beyond the global approach and focus, we plan to incorporate regional climate dynamics with emphasis on processes, integrating multiple environmental proxies wherever available in order to better characterize the mixed layer, and developing a finer time slice within the Mid-Piacenzian Age of the Pliocene, complemented by underused proxies that offer snapshots into environmental conditions. The result will be a proxy-rich, temporally nested, process-oriented approach in a digital format-a relational database with geographic information system capabilities comprising a three-dimensional grid representing the surface layer, with a plethora of data in each cell.

  13. Portable digital micromirror device projector using a prism.

    PubMed

    Pan, Jui-Wen; Wang, Chih-Ming; Sun, Wen-Shing; Chang, Jenq-Yang

    2007-08-01

    A newly designed ultrasmall total internal reflection prism with a size of 29 mm x 22 mm x 24 mm and weight of 19.5 g is proposed for use in a pocket-sized Digital Micromirror Device projector. The entire projector, including an arc lamp illumination, relay, and projection system, has a height of 48 mm and a footprint of 80 mm x 132 mm. By using an overdriving f/2.0 projection lens, the geometric efficiency of the projection system, eta(geo-pro), can be enhanced from 80% to 92%. Although, at the same time, the contrast decreased from 1200:1 to 500:1, this can be enhanced using an off-axis stop. By tuning the position of the stop, the contrast can be as high as 3700:1 for a eta(geo-pro) equal to 90%. Using what we believe to be a novel prism design, we can get a very compact optical system with a high efficiency and good contrast ratio.

  14. PRISM: a data management system for high-throughput proteomics.

    PubMed

    Kiebel, Gary R; Auberry, Ken J; Jaitly, Navdeep; Clark, David A; Monroe, Matthew E; Peterson, Elena S; Tolić, Nikola; Anderson, Gordon A; Smith, Richard D

    2006-03-01

    Advanced proteomic research efforts involving areas such as systems biology or biomarker discovery are enabled by the use of high level informatics tools that allow the effective analysis of large quantities of differing types of data originating from various studies. Performing such analyses on a large scale is not feasible without a computational platform that performs data processing and management tasks. Such a platform must be able to provide high-throughput operation while having sufficient flexibility to accommodate evolving data analysis tools and methodologies. The Proteomics Research Information Storage and Management system (PRISM) provides a platform that serves the needs of the accurate mass and time tag approach developed at Pacific Northwest National Laboratory. PRISM incorporates a diverse set of analysis tools and allows a wide range of operations to be incorporated by using a state machine that is accessible to independent, distributed computational nodes. The system has scaled well as data volume has increased over several years, while allowing adaptability for incorporating new and improved data analysis tools for more effective proteomics research.

  15. Generation of High Resolution Global DSM from ALOS PRISM

    NASA Astrophysics Data System (ADS)

    Takaku, J.; Tadono, T.; Tsutsui, K.

    2014-04-01

    Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM), one of onboard sensors carried on the Advanced Land Observing Satellite (ALOS), was designed to generate worldwide topographic data with its optical stereoscopic observation. The sensor consists of three independent panchromatic radiometers for viewing forward, nadir, and backward in 2.5 m ground resolution producing a triplet stereoscopic image along its track. The sensor had observed huge amount of stereo images all over the world during the mission life of the satellite from 2006 through 2011. We have semi-automatically processed Digital Surface Model (DSM) data with the image archives in some limited areas. The height accuracy of the dataset was estimated at less than 5 m (rms) from the evaluation with ground control points (GCPs) or reference DSMs derived from the Light Detection and Ranging (LiDAR). Then, we decided to process the global DSM datasets from all available archives of PRISM stereo images by the end of March 2016. This paper briefly reports on the latest processing algorithms for the global DSM datasets as well as their preliminary results on some test sites. The accuracies and error characteristics of datasets are analyzed and discussed on various fields by the comparison with existing global datasets such as Ice, Cloud, and land Elevation Satellite (ICESat) data and Shuttle Radar Topography Mission (SRTM) data, as well as the GCPs and the reference airborne LiDAR/DSM.

  16. IL18 Gene Variants Influence the Susceptibility to Chagas Disease.

    PubMed

    Leon Rodriguez, Daniel A; Carmona, F David; Echeverría, Luis Eduardo; González, Clara Isabel; Martin, Javier

    2016-03-01

    Chagas disease is a parasitic disorder caused by the infection with the flagellated protozoan Trypanosoma cruzi. According to the World Health Organization, more than six million people are currently infected in endemic regions. Genetic factors have been proposed to influence predisposition to infection and development of severe clinical phenotypes like chronic Chagas cardiomyopathy (CCC). Interleukin 18 (IL18) encodes a proinflammatory cytokine that has been proposed to be involved in controlling T. cruzi infection. In this study, we analyzed the possible role of six IL18 gene variants (rs5744258, rs360722, rs2043055, rs187238, rs1946518 and rs360719), which cover most of the variation within the locus, in the susceptibility to infection by T. cruzi and/or CCC. In total, 1,171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n = 595), seropositive asymptomatic (n = 175) and CCC (n = 401), were genotyped using TaqMan probes. Significant associations with T. cruzi infection were observed when comparing seronegative and seropositive individuals for rs187238 (P = 2.18E-03, OR = 0.77), rs360719 (P = 1.49E-03, OR = 0.76), rs2043055 (P = 2.52E-03, OR = 1.29), and rs1946518 (P = 0.0162, OR = 1.22). However, dependence analyses suggested that the association was mainly driven by the polymorphism rs360719. This variant is located within the promoter region of the IL18 gene, and it has been described that it creates a binding site for the transcription factor OCT-1 affecting IL-18 expression levels. In addition, no evidence of association was observed between any of the analyzed IL18 gene polymorphisms and the development of CCC. In summary, our data suggest that genetic variation within the promoter region of IL18 is directly involved in the susceptibility to infection by T. cruzi, which provides novel insight into disease pathophysiology and adds new perspectives to achieve a more effective disease control.

  17. Retracing Micro-Epidemics of Chagas Disease Using Epicenter Regression

    PubMed Central

    Levy, Michael Z.; Small, Dylan S.; Vilhena, Daril A.; Bowman, Natalie M.; Kawai, Vivian; Cornejo del Carpio, Juan G.; Cordova-Benzaquen, Eleazar; Gilman, Robert H.; Bern, Caryn; Plotkin, Joshua B.

    2011-01-01

    Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al español disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1 PMID:21935346

  18. Ergosterol biosynthesis and drug development for Chagas disease.

    PubMed

    Urbina, Julio A

    2009-07-01

    This article presents an overview of the currently available drugs nifurtimox (NFX) and benznidazole (BZN) used against Trypanosoma cruzi, the aetiological agent of Chagas disease; herein we discuss their limitations along with potential alternatives with a focus on ergosterol biosynthesis inhibitors (EBI). These compounds are currently the most advanced candidates for new anti-T. cruzi agents given that they block de novo production of 24-alkyl-sterols, which are essential for parasite survival and cannot be replaced by a host's own cholesterol. Among these compounds, new triazole derivatives that inhibit the parasite's C14alpha sterol demethylase are the most promising, as they have been shown to have curative activity in murine models of acute and chronic Chagas disease and are active against NFX and BZN-resistant T. cruzi strains; among this class of compounds, posaconazole (Schering-Plough Research Institute) and ravuconazole (Eisai Company) are poised for clinical trials in Chagas disease patients in the short term. Other T. cruzi-specific EBI, with in vitro and in vivo potency, include squalene synthase, lanosterol synthase and squalene epoxidase-inhibitors as well as compounds with dual mechanisms of action (ergosterol biosynthesis inhibition and free radical generation), but they are less advanced in their development process. The main putative advantages of EBI over currently available therapies include their higher potency and selectivity in both acute and chronic infections, activity against NFX and BZN-resistant T. cruzi strains, and much better tolerability and safety profiles. Limitations may include complexity and cost of manufacture of the new compounds. As for any new drug, such compounds will require extensive clinical testing before being introduced for clinical use, and the complexity of such studies, particularly in chronic patients, will be compounded by the current limitations in the verification of true parasitological cures for T. cruzi

  19. Resveratrol Reverses Functional Chagas Heart Disease in Mice.

    PubMed

    Vilar-Pereira, Glaucia; Carneiro, Vitor C; Mata-Santos, Hilton; Vicentino, Amanda R R; Ramos, Isalira P; Giarola, Naira L L; Feijó, Daniel F; Meyer-Fernandes, José R; Paula-Neto, Heitor A; Medei, Emiliano; Bozza, Marcelo T; Lannes-Vieira, Joseli; Paiva, Claudia N

    2016-10-01

    Chronic chagasic cardiomyopathy (CCC) develops years after acute infection by Trypanosoma cruzi and does not improve after trypanocidal therapy, despite reduction of parasite burden. During disease, the heart undergoes oxidative stress, a potential causative factor for arrhythmias and contractile dysfunction. Here we tested whether antioxidants/ cardioprotective drugs could improve cardiac function in established Chagas heart disease. We chose a model that resembles B1-B2 stage of human CCC, treated mice with resveratrol and performed electrocardiography and echocardiography studies. Resveratrol reduced the prolonged PR and QTc intervals, increased heart rates and reversed sinus arrhythmia, atrial and atrioventricular conduction disorders; restored a normal left ventricular ejection fraction, improved stroke volume and cardiac output. Resveratrol activated the AMPK-pathway and reduced both ROS production and heart parasite burden, without interfering with vascularization or myocarditis intensity. Resveratrol was even capable of improving heart function of infected mice when treatment was started late after infection, while trypanocidal drug benznidazole failed. We attempted to mimic resveratrol's actions using metformin (AMPK-activator) or tempol (SOD-mimetic). Metformin and tempol mimicked the beneficial effects of resveratrol on heart function and decreased lipid peroxidation, but did not alter parasite burden. These results indicate that AMPK activation and ROS neutralization are key strategies to induce tolerance to Chagas heart disease. Despite all tissue damage observed in established Chagas heart disease, we found that a physiological dysfunction can still be reversed by treatment with resveratrol, metformin and tempol, resulting in improved heart function and representing a starting point to develop innovative therapies in CCC.

  20. Chagas disease diagnostic applications: present knowledge and future steps

    PubMed Central

    Balouz, Virginia; Agüero, Fernán; Buscaglia, Carlos A.

    2017-01-01

    Chagas disease, caused by the protozoan Trypanosoma cruzi, is a life-long and debilitating illness of major significance throughout Latin America, and an emergent threat to global public health. Being a neglected disease, the vast majority of Chagasic patients have limited access to proper diagnosis and treatment, and there is only a marginal investment into R&D for drug and vaccine development. In this context, identification of novel biomarkers able to transcend the current limits of diagnostic methods surfaces as a main priority in Chagas disease applied research. The expectation is that these novel biomarkers will provide reliable, reproducible and accurate results irrespective of the genetic background, infecting parasite strain, stage of disease, and clinical-associated features of Chagasic populations. In addition, they should be able to address other still unmet diagnostic needs, including early detection of congenital T. cruzi transmission, rapid assessment of treatment efficiency or failure, indication/prediction of disease progression and direct parasite typification in clinical samples. The lack of access of poor and neglected populations to essential diagnostics also stress the necessity of developing new methods operational in Point-of-Care (PoC) settings. In summary, emergent diagnostic tests integrating these novel and tailored tools should provide a significant impact on the effectiveness of current intervention schemes and on the clinical management of Chagasic patients. In this chapter, we discuss the present knowledge and possible future steps in Chagas disease diagnostic applications, as well as the opportunity provided by recent advances in high-throughput methods for biomarker discovery. PMID:28325368

  1. Resveratrol Reverses Functional Chagas Heart Disease in Mice

    PubMed Central

    Mata-Santos, Hilton; Vicentino, Amanda R. R.; Feijó, Daniel F.; Meyer-Fernandes, José R.; Paula-Neto, Heitor A.; Medei, Emiliano; Bozza, Marcelo T.; Lannes-Vieira, Joseli; Paiva, Claudia N.

    2016-01-01

    Chronic chagasic cardiomyopathy (CCC) develops years after acute infection by Trypanosoma cruzi and does not improve after trypanocidal therapy, despite reduction of parasite burden. During disease, the heart undergoes oxidative stress, a potential causative factor for arrhythmias and contractile dysfunction. Here we tested whether antioxidants/ cardioprotective drugs could improve cardiac function in established Chagas heart disease. We chose a model that resembles B1-B2 stage of human CCC, treated mice with resveratrol and performed electrocardiography and echocardiography studies. Resveratrol reduced the prolonged PR and QTc intervals, increased heart rates and reversed sinus arrhythmia, atrial and atrioventricular conduction disorders; restored a normal left ventricular ejection fraction, improved stroke volume and cardiac output. Resveratrol activated the AMPK-pathway and reduced both ROS production and heart parasite burden, without interfering with vascularization or myocarditis intensity. Resveratrol was even capable of improving heart function of infected mice when treatment was started late after infection, while trypanocidal drug benznidazole failed. We attempted to mimic resveratrol’s actions using metformin (AMPK-activator) or tempol (SOD-mimetic). Metformin and tempol mimicked the beneficial effects of resveratrol on heart function and decreased lipid peroxidation, but did not alter parasite burden. These results indicate that AMPK activation and ROS neutralization are key strategies to induce tolerance to Chagas heart disease. Despite all tissue damage observed in established Chagas heart disease, we found that a physiological dysfunction can still be reversed by treatment with resveratrol, metformin and tempol, resulting in improved heart function and representing a starting point to develop innovative therapies in CCC. PMID:27788262

  2. Retracing micro-epidemics of Chagas disease using epicenter regression.

    PubMed

    Levy, Michael Z; Small, Dylan S; Vilhena, Daril A; Bowman, Natalie M; Kawai, Vivian; Cornejo del Carpio, Juan G; Cordova-Benzaquen, Eleazar; Gilman, Robert H; Bern, Caryn; Plotkin, Joshua B

    2011-09-01

    Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al español disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1.

  3. Chagas' achalasia treated by a jejunal interposed segment.

    PubMed

    Dantas, A N; Carvalho, J L; Coelho, F K; Teixeira, A M; Lyra, L G; Rebouças, G; Didier, F V

    1975-01-01

    Resection of the achalasic area and replacement by a segment of jejunal loop, associated with vagotomy and pyloroplasty, has been performed in 21 patients. The majority of these patients had Chagas' disease, with a dilated esophagus wider than 7 cm. This surgical procedure offered symptomatic relief in 20 of our 21 cases. One patient died, but the death was not necessarily related to the operation. Although disphagia and regurgitation did not disappear entirely in all cases the decrease in severity of these symptoms was such to allow the few symptomatic patients to lead an entirely normal life after the operation.

  4. Diagnosis of Chagas' cardiomyopathy. Non-invasive techniques.

    PubMed Central

    Puigbó, J. J.; Valecillos, R.; Hirschhaut, E.; Giordano, H.; Boccalandro, I.; Suárez, C.; Aparicio, J. M.

    1977-01-01

    The natural history of Chagas' disease and its manifestations when the heart is involved are detailed clinically and pathologically. Three phases are recognized: the acute phase, lasting from 1-3 months, the latent phase, which may last from 10-20 years, and the chronic phase, which has the most serious manifestations. This phase is subdivided into three clinical stages. An analysis of the varied cardiac manifestations on 235 patients is included. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:412174

  5. Sylvatic focus of Chagas' disease in Oaxaca, Mexico.

    PubMed

    Rojas, J C; Malo, E A; Espinoza-Medinilla, E; Ondarza, R N

    1989-04-01

    During three field trips to the community of 'La Humedad', municipality of Santiago Jamiltepec, Oaxaca (a State in the southern part of the Mexican Republic), live specimens of Triatoma mazzottii Usinger (Hemiptera: Reduviidae) were found infected with Trypanosoma cruzi. The insects were captured in only one of the dwellings inspected in the locality, and in four small caves where bats and other mammals live. These findings suggest the need for further studies on the existence of a sylvatic cycle of Chagas' disease in Mexico, which has not yet been established.

  6. Tropical diseases encountered in Canada: 1. Chagas' disease.

    PubMed Central

    Schipper, H.; McClarty, B. M.; McRuer, K. E.; Nash, R. A.; Penney, C. J.

    1980-01-01

    Chagas' disease, or South American trypanosomiasis, is an endemic South American disease now being seen in Canada in both acute and chronic forms. It is characterized by an initial parasitemia that elicits a brisk immune response. Evidence is mounting that the debilitating chronic form, which is characterized by cardiac and visceral organ failure, results from antigenic cross-reactivity between the parasite and the human host, which generates an aberrant, destructive, cell-mediated immune response. Diagnosis, treatment and potential areas for investigation are discussed. PMID:6767543

  7. Structural geological evidence from ODP Leg 131 regarding fluid flow in the Nankai prism, Japan

    NASA Astrophysics Data System (ADS)

    Maltman, Alex; Byrne, Tim; Karig, Dan; Lallemant, Siegfried; Leg 131 Shipboard Party

    1992-04-01

    The fluid flow regime of accretionary prisms influences their morphology and dynamics, and is closely interrelated with deformation. For example, the Lesser Antilles prism shows drainage principally along channels provided by tectonic structures such as thrusts and the basal decollement. A similar behaviour has been suggested for the Nankai prism, and this was investigated during ODP Leg 131. Coring at site 808 penetrated the entire prism and underthrust sediments, and allowed detailed documentation of structures seen in the cores. However, neither the frontal thrust nor the decollement show any visible sign of channelised fluid flow. No veins, mineralised surfaces or clastic dykes were observed. The single clastic dyke seen within the prism appears unrelated to a deformation zone. On the other hand, small-scale structures such as faults and deformation bands are unusually numerous in the Nankai prism, and colour and diagenetic changes within them suggest that they may have acted as micro-conduits for drainage. Further contrasts with other prisms are shown by the sequence of deformation at Nankai and the relative paucity of deformation in the underthrust material. Therefore, the tectonic and fluid flow regime at site 808 differs from the expected pattern. Marked increase in porosity immediately below the decollement hints at overpressuring in this zone, but the structures show no record of localised fluid activity. The structural geological observations throughout the Nankai prism are more consistent with bulk, pervasive dewatering, perhaps utilising the abundant deformation microstructures.

  8. Characteristics Of Imaging By Reflecting Prisms In Turning At Large Angle

    NASA Astrophysics Data System (ADS)

    Zhijian, Wang; Bixin, Deng

    1987-01-01

    The change in image caused by turning reflecting prism in a large angle has been discussed in this paper. Moving image characteristic of the reflecting prism is expressed by characteristic direction and image deflection extreme value plane, it provides the theory basis for designing, scanning and tracing instruments.

  9. Hierarchically triangular prism structured Co3O4: Self-supported fabrication and photocatalytic property

    EPA Science Inventory

    The formation of ammonium cobalt (II) phosphate was utilized to synthesize unprecedented 3D structures of Co3O4, triangular prisms and trunk-like structures, via a self-supported and organics-free method. The length of a triangular side of the prepared 3D triangular prisms is ~1...

  10. Optimisation of the prism coupling of optical whispering-gallery-mode microcavities

    NASA Astrophysics Data System (ADS)

    Demchenko, Yu A.; Bilenko, I. A.; Gorodetsky, M. L.

    2017-08-01

    The methods for increasing the coupling efficiency of a prism with spheroidal microcavities, aimed at exciting whisperinggallery modes, have been analytically investigated. Optimal angles of incidence and incident beam parameters are obtained for a spheroidal cavity. The cavity eigenfrequency shift caused by the presence of a prism and the introduced loss by it is calculated.

  11. Standardization of motion sickness induced by left-right and up-down reversing prisms

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Vanderploeg, J. M.; Brumley, E. A.; Kolafa, J. J.; Wood, S. J.

    1990-01-01

    Reversing prisms are known to produce symptoms of motion sickness, and have been used to provide a chronic stimulus for training subjects on symptom recognition and regulation. However, testing procedures with reversing prisms have not been standardized. A set of procedures were evaluated which could be standardized using prisms for provocation and to compare the results between Right/Left Reversing Prisms (R/L-RP) and Up/Down Reversing Prisms (U/D-RP). Fifteen subjects were tested with both types of prisms using a self paced walking course throughout the laboratory with work stations established at specified intervals. The work stations provided tasks requiring eye-hand-foot coordination and various head movements. Comparisons were also made between these prism tests and two other standardized susceptibility tests, the KC-135 parabolic static chair test and the Staircase Velocity Motion Test (SVMT). Two different types of subjective symptom reports were compared. The R/L-RP were significantly more provocative than the U/D-RP. The incidence of motion sickness symptoms for the R/L-RP was similar to the KC-135 parabolic static chair test. Poor correlations were found between the prism tests and the other standardized susceptibility tests, which might indicate that different mechanisms are involved in provoking motion sickness for these different tests.

  12. Prism Foil from an LCD Monitor as a Tool for Teaching Introductory Optics

    ERIC Educational Resources Information Center

    Planinsic, Gorazd; Gojkosek, Mihael

    2011-01-01

    Transparent prism foil is part of a backlight system in LCD monitors that are widely used today. This paper describes the optical properties of the prism foil and several pedagogical applications suitable for undergraduate introductory physics level. Examples include experiments that employ refraction, total internal reflection, diffraction and…

  13. Investigating First Year Elementary Mathematics Teacher Education Students' Knowledge of Prism

    ERIC Educational Resources Information Center

    Bozkurt, Ali; Koc, Yusuf

    2012-01-01

    The purpose of this study was to investigate first year elementary mathematics teacher education students' knowledge of prism. For this goal, the participants were asked to define the geometric concept of prism. The participants were 158 first year elementary mathematics teacher education students from a public university in Southern Turkey. The…

  14. Impact of high power and angle of incidence on prism corrections for visual field loss

    PubMed Central

    Jung, Jae-Hyun; Peli, Eli

    2014-01-01

    Prism distortions and spurious reflections are not usually considered when prescribing prisms to compensate for visual field loss due to homonymous hemianopia. Distortions and reflections in the high power Fresnel prisms used in peripheral prism placement can be considerable, and the simplifying assumption that prism deflection power is independent of angle of incidence into the prisms results in substantial errors. We analyze the effects of high prism power and incidence angle on the field expansion, size of the apical scotomas, and image compression/expansion. We analyze and illustrate the effects of reflections within the Fresnel prisms, primarily due to reflections at the bases, and secondarily due to surface reflections. The strength and location of these effects differs materially depending on whether the serrated prismatic surface is placed toward or away from the eye, and this affects the contribution of the reflections to visual confusion, diplopia, false alarms, and loss of contrast. We conclude with suggestions for controlling and mitigating these effects in clinical practice. PMID:24497649

  15. Standardization of motion sickness induced by left-right and up-down reversing prisms

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Vanderploeg, J. M.; Brumley, E. A.; Kolafa, J. J.; Wood, S. J.

    1990-01-01

    Reversing prisms are known to produce symptoms of motion sickness, and have been used to provide a chronic stimulus for training subjects on symptom recognition and regulation. However, testing procedures with reversing prisms have not been standardized. A set of procedures were evaluated which could be standardized using prisms for provocation and to compare the results between Right/Left Reversing Prisms (R/L-RP) and Up/Down Reversing Prisms (U/D-RP). Fifteen subjects were tested with both types of prisms using a self paced walking course throughout the laboratory with work stations established at specified intervals. The work stations provided tasks requiring eye-hand-foot coordination and various head movements. Comparisons were also made between these prism tests and two other standardized susceptibility tests, the KC-135 parabolic static chair test and the Staircase Velocity Motion Test (SVMT). Two different types of subjective symptom reports were compared. The R/L-RP were significantly more provocative than the U/D-RP. The incidence of motion sickness symptoms for the R/L-RP was similar to the KC-135 parabolic static chair test. Poor correlations were found between the prism tests and the other standardized susceptibility tests, which might indicate that different mechanisms are involved in provoking motion sickness for these different tests.

  16. Partners in Portraiture: An Account of the Collaborative Work of Projects PRISM and Co-Arts.

    ERIC Educational Resources Information Center

    Kaiser, Jon E.; And Others

    The evolution and implementation of a collaborative effort between an elementary school bilingual science education project (Process in Science Methods, or PRISM) of The Network, Inc., and a study of the educational effectiveness of community arts centers (Project Co-Arts) are described. With PRISM's focus on science and Co-Arts' concentration on…

  17. Hierarchically triangular prism structured Co3O4: Self-supported fabrication and photocatalytic property

    EPA Science Inventory

    The formation of ammonium cobalt (II) phosphate was utilized to synthesize unprecedented 3D structures of Co3O4, triangular prisms and trunk-like structures, via a self-supported and organics-free method. The length of a triangular side of the prepared 3D triangular prisms is ~1...

  18. Prism Foil from an LCD Monitor as a Tool for Teaching Introductory Optics

    ERIC Educational Resources Information Center

    Planinsic, Gorazd; Gojkosek, Mihael

    2011-01-01

    Transparent prism foil is part of a backlight system in LCD monitors that are widely used today. This paper describes the optical properties of the prism foil and several pedagogical applications suitable for undergraduate introductory physics level. Examples include experiments that employ refraction, total internal reflection, diffraction and…

  19. Prism adaptation enhances activity of intact fronto-parietal areas in both hemispheres in neglect patients.

    PubMed

    Saj, Arnaud; Cojan, Yann; Vocat, Roland; Luauté, Jacques; Vuilleumier, Patrik

    2013-01-01

    Unilateral spatial neglect involves a failure to report or orient to stimuli in the contralesional (left) space due to right brain damage, with severe handicap in everyday activities and poor rehabilitation outcome. Because behavioral studies suggest that prism adaptation may reduce spatial neglect, we investigated the neural mechanisms underlying prism effects on visuo-spatial processing in neglect patients. We used functional magnetic resonance imaging (fMRI) to examine the effect of (right-deviating) prisms on seven patients with left neglect, by comparing brain activity while they performed three different spatial tasks on the same visual stimuli (bisection, search, and memory), before and after a single prism-adaptation session. Following prism adaptation, fMRI data showed increased activation in bilateral parietal, frontal, and occipital cortex during bisection and visual search, but not during the memory task. These increases were associated with significant behavioral improvement in the same two tasks. Changes in neural activity and behavior were seen only after prism adaptation, but not attributable to mere task repetition. These results show for the first time the neural substrates underlying the therapeutic benefits of prism adaptation, and demonstrate that visuo-motor adaptation induced by prism exposure can restore activation in bilateral brain networks controlling spatial attention and awareness. This bilateral recruitment of fronto-parietal networks may counteract the pathological biases produced by unilateral right hemisphere damage, consistent with recent proposals that neglect may reflect lateralized deficits induced by bilateral hemispheric dysfunction. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. PRISM 3: expanded prediction of natural product chemical structures from microbial genomes

    PubMed Central

    Skinnider, Michael A.; Merwin, Nishanth J.; Johnston, Chad W.

    2017-01-01

    Abstract Microbial natural products represent a rich resource of pharmaceutically and industrially important compounds. Genome sequencing has revealed that the majority of natural products remain undiscovered, and computational methods to connect biosynthetic gene clusters to their corresponding natural products therefore have the potential to revitalize natural product discovery. Previously, we described PRediction Informatics for Secondary Metabolomes (PRISM), a combinatorial approach to chemical structure prediction for genetically encoded nonribosomal peptides and type I and II polyketides. Here, we present a ground-up rewrite of the PRISM structure prediction algorithm to derive prediction of natural products arising from non-modular biosynthetic paradigms. Within this new version, PRISM 3, natural product scaffolds are modeled as chemical graphs, permitting structure prediction for aminocoumarins, antimetabolites, bisindoles and phosphonate natural products, and building upon the addition of ribosomally synthesized and post-translationally modified peptides. Further, with the addition of cluster detection for 11 new cluster types, PRISM 3 expands to detect 22 distinct natural product cluster types. Other major modifications to PRISM include improved sequence input and ORF detection, user-friendliness and output. Distribution of PRISM 3 over a 300-core server grid improves the speed and capacity of the web application. PRISM 3 is available at http://magarveylab.ca/prism/. PMID:28460067

  1. Impact of high power and angle of incidence on prism corrections for visual field loss

    NASA Astrophysics Data System (ADS)

    Jung, Jae-Hyun; Peli, Eli

    2014-06-01

    Prism distortions and spurious reflections are not usually considered when prescribing prisms to compensate for visual field loss due to homonymous hemianopia. Distortions and reflections in the high-power Fresnel prisms used in peripheral prism placement can be considerable, and the simplifying assumption that prism deflection power is independent of angle of incidence into the prisms results in substantial errors. We analyze the effects of high prism power and incidence angle on the field expansion, size of the apical scotomas, and image compression/expansion. We analyze and illustrate the effects of reflections within the Fresnel prisms, primarily due to reflections at the bases, and secondarily due to surface reflections. The strength and location of these effects differs materially depending on whether the serrated prismatic surface is placed toward or away from the eye, and this affects the contribution of the reflections to visual confusion, diplopia, false alarms, and loss of contrast. We conclude with suggestions for controlling and mitigating these effects in clinical practice.

  2. Electrocardiographic and echocardiographic abnormalities in Chagas disease: findings in residents of rural Bolivian communities hyperendemic for Chagas disease.

    PubMed

    Fernandez, Antonio B; Nunes, Maria Carmo P; Clark, Eva H; Samuels, Aaron; Menacho, Silvio; Gomez, Jesus; Bozo Gutierrez, Ricardo W; Crawford, Thomas C; Gilman, Robert H; Bern, Caryn

    2015-09-01

    Chagas disease is a neglected and preventable tropical disease that causes significant cardiac morbidity and mortality in Latin America. This study sought to describe cardiac findings among inhabitants of rural communities of the Bolivian Chaco. The cardiac study drew participants from an epidemiologic study in 7 indigenous Guarani communities. All infected participants 10 years or older were asked to undergo a brief physical examination and 12-lead electrocardiogram (ECG). A subset had echocardiograms. ECG and echocardiograms were read by 1 or more cardiologists. Of 1,137 residents 10 years or older, 753 (66.2%) had Trypanosoma cruzi infection. Cardiac evaluations were performed for 398 infected participants 10 years or older. Fifty-five participants (13.8%) had 1 or more ECG abnormalities suggestive of Chagas cardiomyopathy. The most frequent abnormalities were bundle branch blocks in 42 (11.3%), followed by rhythm disturbances or ventricular ectopy in 13 (3.3%), and atrioventricular blocks (AVB) in 10 participants (2.6%). The prevalence of any abnormality rose from 1.1% among those 10 to 19 years old to 14.2%, 17.3%, and 26.4% among those 20 to 39, 40 to 59, and older than 60 years, respectively. First-degree AVB was seen most frequently in participants 60 years or older, but the 4 patients with third-degree AVB were all under 50 years old. Eighteen and 2 participants had a left ventricular ejection fraction of 40% to 54% and <40%, respectively. An increasing number of ECG abnormalities was associated with progressively larger left ventricular end-diastolic dimensions and lower left ventricular ejection fraction. We found a high prevalence of ECG abnormalities and substantial evidence of Chagas cardiomyopathy. Programs to improve access to basic cardiac care (annual ECG, antiarrhythmics, pacemakers) could have an immediate impact on morbidity and mortality in these highly endemic communities. Copyright © 2015 World Heart Federation (Geneva). All rights reserved.

  3. When a misperception favors a tragedy: Carlos Chagas and the Nobel Prize of 1921.

    PubMed

    Bestetti, Reinaldo B; Couto, Lucélio B; Cardinalli-Neto, Augusto

    2013-11-20

    Carlos Chagas, the discoverer of Chagas' disease was nominated to the Nobel Prize in 1921, but none did win the prize in that year. As a leader of a young scientist team, he discovered all aspects of the new disease from 1909 to 1920. It is still obscure why he did not win the Nobel Prize in 1921. Chagas was discarded by Gunnar Hedrèn on April 16, 1921. Hedrèn should have made a written report about the details of his evaluation to the Nobel Committee. However, such a document has not been found in the Nobel Committee Archives. No evidence of detractions made by Brazilian scientists on Chagas was found. Since Chagas nomination was consistent with the Nobel Committee requirements, as seen in the presentation letter by until now unknown Cypriano de Freitas, it become clear that Chagas did not win the Nobel Prize exclusively because the Nobel Committee did not perceive the importance of his discovery. Thus, it would be fair a posthumous Nobel Prize of 1921 to Carlos Chagas. A diploma of the Nobel Prize, as precedent with Dogmack in 1947, would recognize the merit of the scientist who made the most complete medical discovery of all times.

  4. Chagas disease awareness among Latin American immigrants living in Los Angeles, California.

    PubMed

    Sanchez, Daniel R; Traina, Mahmoud I; Hernandez, Salvador; Smer, Aiman M; Khamag, Haneen; Meymandi, Sheba K

    2014-11-01

    Approximately 300,000 persons have Chagas disease in the United States, although almost all persons acquired the disease in Latin America. We examined awareness of Chagas disease among Latin American immigrants living in Los Angeles, California. We surveyed 2,677 persons (age range = 18-60 years) in Los Angeles who resided in Latin America for at least six months. A total of 62% of the participants recalled seeing triatomines in Latin America, and 27% of the participants reported triatomine bites at least once per year while living abroad. A total of 86% of the participants had never heard of Chagas disease. Of persons who had heard of Chagas disease, 81% believed that it was not serious. More than 95% of those who had heard of Chagas disease would want to be tested and treated. Most Latin American immigrants living in Los Angeles recalled exposure to vectors of Chagas disease. However, they have little knowledge of this disease. Increasing awareness of Chagas disease is needed in this high-risk population.

  5. Chagas Disease Awareness among Latin American Immigrants Living in Los Angeles, California

    PubMed Central

    Sanchez, Daniel R.; Traina, Mahmoud I.; Hernandez, Salvador; Smer, Aiman M.; Khamag, Haneen; Meymandi, Sheba K.

    2014-01-01

    Approximately 300,000 persons have Chagas disease in the United States, although almost all persons acquired the disease in Latin America. We examined awareness of Chagas disease among Latin American immigrants living in Los Angeles, California. We surveyed 2,677 persons (age range = 18–60 years) in Los Angeles who resided in Latin America for at least six months. A total of 62% of the participants recalled seeing triatomines in Latin America, and 27% of the participants reported triatomine bites at least once per year while living abroad. A total of 86% of the participants had never heard of Chagas disease. Of persons who had heard of Chagas disease, 81% believed that it was not serious. More than 95% of those who had heard of Chagas disease would want to be tested and treated. Most Latin American immigrants living in Los Angeles recalled exposure to vectors of Chagas disease. However, they have little knowledge of this disease. Increasing awareness of Chagas disease is needed in this high-risk population. PMID:25200261

  6. Risks of endemicity, morbidity and perspectives regarding the control of Chagas disease in the Amazon Region.

    PubMed

    Coura, José Rodrigues; Junqueira, Angela Cv

    2012-03-01

    Chagas disease, in the Amazon Region as elsewhere, can be considered an enzootic disease of wild animals or an anthropozoonosis, an accidental disease of humans that is acquired when humans penetrate a wild ecosystem or when wild triatomines invade human dwellings attracted by light or searching for human blood. The risk of endemic Chagas disease in the Amazon Region is associated with the following phenomena: (i) extensive deforestation associated with the displacement of wild mammals, which are the normal sources of blood for triatomines, (ii) adaptation of wild triatomines to human dwellings due to the need for a new source of blood for feeding and (iii) uncontrolled migration of human populations and domestic animals that are already infected with Trypanosoma cruzi from areas endemic for Chagas disease to the Amazon Region. Several outbreaks of severe acute cases of Chagas disease, as well as chronic cases, have been described in the Amazon Region. Control measures targeted to avoiding endemic Chagas disease in the Amazon Region should be the following: improving health education in communities, training public health officials and communities for vector and Chagas disease surveillance and training local physicians to recognise and treat acute and chronic cases of Chagas diseases as soon as possible.

  7. Mortality Related to Chagas Disease and HIV/AIDS Coinfection in Brazil

    PubMed Central

    Martins-Melo, Francisco Rogerlândio; Ramos, Alberto Novaes; Alencar, Carlos Henrique; Heukelbach, Jorg

    2012-01-01

    Chagas disease in patients with HIV infection represents a potentially serious event with high case fatality rates. This study describes epidemiological and clinical aspects of deaths related to Chagas disease and HIV/AIDS coinfection in Brazil, 1999–2007. We performed a descriptive study based on mortality data from the nationwide Mortality Information System. Of a total of about 9 million deaths, Chagas disease and HIV/AIDS were mentioned in the same death certificate in 74 cases. AIDS was an underlying cause in 77.0% (57) and Chagas disease in 17.6% (13). Males (51.4%), white skin color (50%), age group 40–49 years (29.7%), and residents in the Southeast region (75.7%) were most common. Mean age at death was significantly lower in the coinfected (47.1 years [SD ± 14.6]), as compared to Chagas disease deaths (64.1 years [SD ± 14.7], P < 0.001). Considering the lack of data on morbidity related to Chagas disease and AIDS coinfection, the use of mortality data may be an appropriate sentinel approach to monitor the occurrence of this association. Due to the epidemiological transition in Brazil, chronic Chagas disease and HIV/AIDS coinfection will be further complicated and require the development of evidence-based preventive control measures. PMID:22969814

  8. PRISM-E: Comparison of Integrated Care and Enhanced Specialty Referral in Managing At-Risk Alcohol Use

    PubMed Central

    Oslin, David W.; Grantham, Susan; Coakley, Eugenie; Maxwell, James; Miles, Keith; Ware, James; Blow, Frederic C.; Krahn, Dean D.; Bartels, Stephen J.; Zubritsky, Cynthia

    2011-01-01

    Objective This study was part of the Primary Care Research in Substance Abuse and Mental Health for the Elderly study (PRISM-E) and determined the relative effectiveness of two different models of care for reducing at-risk alcohol use among primary care patients aged 65 and older. Methods This multisite study was a randomized clinical trial comparing integrated care with enhanced specialty referral for older primary care patients screened and identified to have at-risk drinking. Results Before the study, the 560 participants consumed a mean of 17.9 drinks per week and had a mean of 21.1 binge episodes in the prior three months. At six months, both treatment groups reported lower levels of average weekly drinking (p<.001) and binge drinking (p<.001), despite low levels of treatment engagement. However, the declines did not differ significantly between treatment groups. Conclusions These results suggest that older persons with at-risk drinking can substantially modify their drinking over time. Although no evidence suggested that the model of care was important in achieving this result, the magnitude of reduction in alcohol use was comparable with other intervention studies. PMID:16816279

  9. ePRISM: A case study in multiple proxy and mixed temporal resolution integration

    USGS Publications Warehouse

    Robinson, Marci M.; Dowsett, Harry J.

    2010-01-01

    As part of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project, we present the ePRISM experiment designed I) to provide climate modelers with a reconstruction of an early Pliocene warm period that was warmer than the PRISM interval (similar to 3.3 to 3.0 Ma), yet still similar in many ways to modern conditions and 2) to provide an example of how best to integrate multiple-proxy sea surface temperature (SST) data from time series with varying degrees of temporal resolution and age control as we begin to build the next generation of PRISM, the PRISM4 reconstruction, spanning a constricted time interval. While it is possible to tie individual SST estimates to a single light (warm) oxygen isotope event, we find that the warm peak average of SST estimates over a narrowed time interval is preferential for paleoclimate reconstruction as it allows for the inclusion of more records of multiple paleotemperature proxies.

  10. A unit structure Rochon prism based on the extraordinary refraction of uniaxial birefringent crystals.

    PubMed

    Wu, Wendi; Wu, Fuquan; Shi, Meng; Su, Fufang; Han, Peigao; Ma, Lili

    2013-06-03

    Based on the Fermat's principle, the universal theory of refraction and reflection of extraordinary rays (e-rays) in the uniaxial crystal is formulated. Using this theory, a new unit structure prism is designed, and its properties are studied. Based on the theoretical results, such a prism is achieved experimentally by using the Iceland crystal. In both theoretical and experimental studies, this new prism shows excellent polarization splitting performances such as big and adjustable splitting angle, comparing to the conventional Rochon prism. For the sample prism with the optical axis angle of 45°, the splitting angle reaches 19.8°in the normal incidence, and the maximum splitting angle reaches 28.44° while the incidence angle is -4°.

  11. Controlling Orientational Order in 1-D Assemblies of Multivalent Triangular Prisms.

    PubMed

    Kohlstedt, Kevin L; Olvera de la Cruz, Monica; Schatz, George C

    2013-01-03

    Multivalent nanostructures are becoming an increasingly important player in the self-assembly of supramolecular lattices. Understanding the role that shape plays in the coordination of the assemblies is crucial for the functional response of the material. We develop a simple design rule for the assembly of multivalent Au triangular nanoprisms into 1-D ordered arrays based on both the length of the valent DNA and the aspect ratio of the prism. Using MD simulations, we describe an order parameter that captures the short-range order of the assembly controlled by the design parameters. The order parameter shows that even short chains (N = 4) of prisms have a high degree of orientational order that transitions to no orientational order when the DNA length is similar to the prism length. Unlike isotropic polyvalent assemblies, we find that the highly oriented chains of prisms lose orientational order in discrete steps during melting as the prisms in the arrays dissociate.

  12. Features of extraordinary ray propagation in an optically anisotropic birefringent prism

    NASA Astrophysics Data System (ADS)

    Zisser, Iaroslav; Zisser, Irina

    2016-11-01

    Features of ordinary and extraordinary rays travelling through an optically anisotropic prism with total internal reflection on one of the faces are considered in the paper. Special attention is paid to the process of extraordinary ray reflection from the face of total internal reflection. Ray propagation was investigated for prisms made of four optically uniaxial crystals (TeO2, CaCO3, Hg2Cl2, Hg2J2) having different optical signs and values of birefringence. Possible ways of ray propagation through a prism at different angles of incidence on the prism and different directions of ray propagation within the prism were calculated. The examined features allow channels in fiber-optical communication systems to be split by optical means.

  13. Image relocation with prisms in patients with age-related macular degeneration.

    PubMed

    Al-Karmi, Rani; Markowitz, Samuel N

    2006-06-01

    To determine the benefits of image relocation (IR) with prisms in patients with age-related macular degeneration (AMD). This was a retrospective comparative interventional case series of 100 patients with AMD and 5 years of available follow-up records. Participants underwent complete low vision (LV) assessments, including identification of preferred retinal locus (PRL). Prisms were added to prescription glasses to produce IR to the presumed PRL. Main outcome measures were best-corrected visual acuity (BCVA), location of the PRL preferred by the patient for rehabilitation, use of glasses prescribed, and number of prism diopters prescribed. Patients wearing prescribed glasses for distance with prisms for IR showed improved BCVA (t(63) = 9.5, p = 0.001) as did those patients wearing prescribed glasses for distance without prisms for IR (t(14) = 2.25, p = 0.04). Patients wearing prescribed glasses for distance with prisms for IR achieved better BCVA than those patients wearing prescribed glasses for distance without prisms for IR (t(77) = 2.0, p = 0.05). Patients reported using distance glasses with prisms for 3 to 48 months (mean [SD], 8.4 [11.7] mo). Number of prism diopters used (mean [SD], 5.8 [1.9] D) was well tolerated by all patients. PRL preferred by patients was on the upper retina in 98.5% of cases. IR with prisms to PRL in patients with AMD results in a significant and sizable improvement in BCVA. This effect is probably created by facilitation of oculomotor functions resulting from direct reduction of fixation instability.

  14. Successful treatment of diplopia with prism improves health-related quality of life

    PubMed Central

    Hatt, Sarah R.; Leske, David A.; Liebermann, Laura; Holmes, Jonathan M.

    2014-01-01

    Purpose To report change in strabismus-specific health-related quality of life (HRQOL) following treatment with prism. Design Retrospective cross-sectional study Methods Thirty-four patients with diplopia (median age 63, range 14 to 84 years) completed the Adult Strabismus-20 questionnaire (100 to 0, best to worst HRQOL) and a diplopia questionnaire in a clinical practice before prism and in prism correction. Before prism, diplopia was “sometimes” or worse for reading and/or straight ahead distance. Prism treatment success was defined as diplopia rated “never” or “rarely” on the Diplopia Questionnaire for reading and straight ahead distance. Failure was defined as worsening or no change in diplopia. For both successes and failures, mean Adult Strabismus -20 scores were compared pre-prism and in prism correction. Each of the four Adult Strabismus -20 domains (Self-perception, Interactions, Reading function and General function) were analyzed separately. Results Twenty-three (68%) of 34 were successes and 11 (32%) were failures. For successes, Reading Function improved from 57 ± 27 (SD) before prism to 69 ± 27 in-prism correction (difference 12 ± 20, 95% CI 3.2 to 20.8, P=0.02) and General Function improved from 66 ± 25 to 80 ± 18 (difference 14 ± 22, 95% CI 5.0 to 23.6, P=0.003). Self-perception and Interaction domains remained unchanged (P>0.2). For failures there was no significant change in Adult Strabismus -20 score on any domain (P>0.4). Conclusions Successful correction of diplopia with prism is associated with improvement in strabismus-specific HRQOL, specifically reading function and general function. PMID:24561171

  15. Epidemiology, genetics, and subtyping of preserved ratio impaired spirometry (PRISm) in COPDGene.

    PubMed

    Wan, Emily S; Castaldi, Peter J; Cho, Michael H; Hokanson, John E; Regan, Elizabeth A; Make, Barry J; Beaty, Terri H; Han, MeiLan K; Curtis, Jeffrey L; Curran-Everett, Douglas; Lynch, David A; DeMeo, Dawn L; Crapo, James D; Silverman, Edwin K

    2014-08-06

    Preserved Ratio Impaired Spirometry (PRISm), defined as a reduced FEV1 in the setting of a preserved FEV1/FVC ratio, is highly prevalent and is associated with increased respiratory symptoms, systemic inflammation, and mortality. Studies investigating quantitative chest tomographic features, genetic associations, and subtypes in PRISm subjects have not been reported. Data from current and former smokers enrolled in COPDGene (n = 10,192), an observational, cross-sectional study which recruited subjects aged 45-80 with ≥10 pack years of smoking, were analyzed. To identify epidemiological and radiographic predictors of PRISm, we performed univariate and multivariate analyses comparing PRISm subjects both to control subjects with normal spirometry and to subjects with COPD. To investigate common genetic predictors of PRISm, we performed a genome-wide association study (GWAS). To explore potential subgroups within PRISm, we performed unsupervised k-means clustering. The prevalence of PRISm in COPDGene is 12.3%. Increased dyspnea, reduced 6-minute walk distance, increased percent emphysema and decreased total lung capacity, as well as increased segmental bronchial wall area percentage were significant predictors (p-value <0.05) of PRISm status when compared to control subjects in multivariate models. Although no common genetic variants were identified on GWAS testing, a significant association with Klinefelter's syndrome (47XXY) was observed (p-value < 0.001). Subgroups identified through k-means clustering include a putative "COPD-subtype", "Restrictive-subtype", and a highly symptomatic "Metabolic-subtype". PRISm subjects are clinically and genetically heterogeneous. Future investigations into the pathophysiological mechanisms behind and potential treatment options for subgroups within PRISm are warranted. Clinicaltrials.gov Identifier: NCT000608764.

  16. Contributions of Arctic PRISM to monitoring western hemispheric shorebirds

    USGS Publications Warehouse

    Skagen, Susan K.; Smith, Paul A.; Andres, Brad A.; Donaldson, Garry; Brown, Stephen

    2012-01-01

    for assessing its vulnerability and subsequent listing under the U.S. Endangered Species Act and the Canadian Species at Risk Act. To meet the need for information on population size and trends, shorebird biologists from Canada and the United States proposed a shared blueprint for shorebird monitoring across the Western Hemisphere in the late 1990s; this effort was undertaken in concert with the development of the Canadian and U.S. Shorebird Conservation Plans (Donaldson et al. 2000, Brown et aL 2001). Soon thereafter, partners in the monitoring effort adopted the name "Program for Regional and International Shorebird Monitoring" (PRISM). Among the primary objectives of PRISM were to estimate the population sizes and trends of breeding North American shorebirds and describe their distributions (Bart et al. 2002). PRISM members evaluated ongoing and potential monitoring approaches to address 74 taxa (including subspecies) and proposed a combination of arctic andboreal breeding surveys, temperate breeding and non-breeding surveys, and neotropical surveys.

  17. Foreword: contributions of Arctic PRISM to monitoring western hemispheric shorebirds

    USGS Publications Warehouse

    Skagen, Susan K.; Smith, Paul A.; Andres, Brad A.; Donaldson, Garry; Brown, Stephen

    2012-01-01

    listing under the U.S. Endangered Species Act and the Canadian Species at Risk Act. To meet the need for information on population size and trends, shorebird biologists from Canada and the United States proposed a shared blueprint for shorebird monitoring across the Western Hemisphere in the late 1990s; this effort was undertaken in concert with the development of the Canadian and the U.S. Shorebird Conservation Plans. Soon thereafter, partners in the monitoring effort adopted the name "Program for Regional and International Shorebird Monitoring" (PRISM). Among the primary objectives of PRISM were to estimate the population sizes and trends of breeding North American shorebirds and describe their distributions. PRISM members evaluated ongoing and potential monitoring approached to address 74 taxa (including subspecies) and proposed a combination of arctic and boreal breeding surveys, temperate breeding and non-breeding surveys, and neotropical surveys.

  18. Squalene Synthase As a Target for Chagas Disease Therapeutics

    PubMed Central

    Chan, Hsiu-Chien; Li, Jikun; Zheng, Yingying; Huang, Chun-Hsiang; Ren, Feifei; Chen, Chun-Chi; Zhu, Zhen; Galizzi, Melina; Li, Zhu-Hong; Rodrigues-Poveda, Carlos A.; Gonzalez-Pacanowska, Dolores; Veiga-Santos, Phercyles; de Carvalho, Tecia Maria Ulisses; de Souza, Wanderley; Urbina, Julio A.; Wang, Andrew H.-J.; Docampo, Roberto; Li, Kai; Liu, Yi-Liang; Oldfield, Eric; Guo, Rey-Ting

    2014-01-01

    Trypanosomatid parasites are the causative agents of many neglected tropical diseases and there is currently considerable interest in targeting endogenous sterol biosynthesis in these organisms as a route to the development of novel anti-infective drugs. Here, we report the first x-ray crystallographic structures of the enzyme squalene synthase (SQS) from a trypanosomatid parasite, Trypanosoma cruzi, the causative agent of Chagas disease. We obtained five structures of T. cruzi SQS and eight structures of human SQS with four classes of inhibitors: the substrate-analog S-thiolo-farnesyl diphosphate, the quinuclidines E5700 and ER119884, several lipophilic bisphosphonates, and the thiocyanate WC-9, with the structures of the two very potent quinuclidines suggesting strategies for selective inhibitor development. We also show that the lipophilic bisphosphonates have low nM activity against T. cruzi and inhibit endogenous sterol biosynthesis and that E5700 acts synergistically with the azole drug, posaconazole. The determination of the structures of trypanosomatid and human SQS enzymes with a diverse set of inhibitors active in cells provides insights into SQS inhibition, of interest in the context of the development of drugs against Chagas disease. PMID:24789335

  19. Advances in Chagas disease drug development: 2009-2010

    PubMed Central

    Buckner, Frederick S.; Navabi, Nazlee

    2013-01-01

    Purpose of Review The need for better drugs to treat patients with Chagas disease remains urgent. This review summarizes the advancements in drug development over the past two years. Recent Findings Drug development efforts are almost exclusively occurring as preclinical research. The exceptions being Phase I safety studies for the cruzain inhibitor, K-777, and potential Phase II studies for the antifungal drug, posaconazole, and a prodrug of ravuconazole. Several recent laboratory investigations demonstrate anti-T. cruzi activity of novel small molecules in animal models. These include nonpeptidic cruzain inhibitors, novel inhibitors of the sterol 14α-demethylase enzyme, new compounds (arylimidamides) related to pentamidine, derivatives of nifurtimox, compounds using ruthenium complexes, and several natural products. The recent implementation of a high-throughput screen of >300,000 compounds against intracellular T. cruzi amastigotes done at the Broad Institute is an important development, yielding ~300 selective inhibitors, many of which may serve as leads for medicinal chemistry efforts. Summary Progress is slow, but recent advancements in both drug development and advocacy for research on neglected diseases are encouraging. Efforts to define a target product profile and to harmonize methodologies for testing drugs for Chagas disease are described herein. PMID:20885320

  20. Biological factors that impinge on Chagas disease drug development.

    PubMed

    Francisco, Amanda F; Jayawardhana, Shiromani; Lewis, Michael D; Taylor, Martin C; Kelly, John M

    2017-08-23

    Chagas disease is caused by infection with the insect-transmitted protozoan Trypanosoma cruzi, and is the most important parasitic infection in Latin America. The current drugs, benznidazole and nifurtimox, are characterized by limited efficacy and toxic side-effects, and treatment failures are frequently observed. The urgent need for new therapeutic approaches is being met by a combined effort from the academic and commercial sectors, together with major input from not-for-profit drug development consortia. With the disappointing outcomes of recent clinical trials against chronic Chagas disease, it has become clear that an incomplete understanding of parasite biology and disease pathogenesis is impacting negatively on the development of more effective drugs. In addition, technical issues, including difficulties in establishing parasitological cure in both human patients and animal models, have greatly complicated the assessment of drug efficacy. Here, we outline the major questions that need to be addressed and discuss technical innovations that can be exploited to accelerate the drug development pipeline.